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Hypotrichosis simplex (HS) comprises a group of hereditary isolated alopecias that are characterized by a diffuse and progressive loss of hair starting in childhood and shows a wide phenotypic variability. We mapped an autosomal-dominant form of HS to chromosome 1q31.3-1q41 in a Spanish family. By direct sequencing, we identified the heterozygous mutation c.1A>G (p.Met1?) in SNRPE that results in loss of the start codon of the transcript. We identified the same mutation in a simplex HS case from the UK and an additional mutation (c.133G>A [p.Gly45Ser]) in a simplex HS case originating from Tunisia. SNRPE encodes a core protein of U snRNPs, the key factors of the pre-mRNA processing spliceosome. The missense mutation c.133G>A leads to a glycine to senile substitution and is predicted to disrupt the structure of SNRPE. Western blot analyses of HEK293T cells expressing SNRPE c.1A>G revealed an N-terminally truncated protein, and therefore the mutation might result in use of an alternative in-frame downstream start codon. Subcellular localization of mutant SNRPE by immunofluorescence analyses as well as incorporation of mutant SNRPE proteins into U snRNPs was found to be normal, suggesting that the function of U snRNPs in splicing, rather than their biogenesis, is affected. In this report we link a core component of the spliceosome to hair loss, thus adding another specific factor in the complexity of hair growth. Furthermore, our findings extend the range of human phenotypes that are linked to the splicing machinery.

In this study, 117 isolates of Haemophilus parasuis from organs and tissues from pigs showing clinical signs, were characterised and compared with 10 H. parasuis reference strains. The isolates were subjected to the 16S rRNA gene PCR and subsequently serotyped, genotyped by 60-kDa heat shock protein (Hsp60) gene sequences, the enterobacterial repetitive intergenic consensus (ERIC) PCR and a multiplex PCR for the detection of the vtaA virulence associated trimeric autotransporter genes. Serotyping revealed the presence of 13 H. parasuis serovars. Serovars 3 and 10 were not detected, and 16 of the 117 H. parasuis isolates could not be typed by specific antisera. All isolates were positive in the 16S rRNA gene specific H. parasuis PCR. ERIC-PCR revealed a very heterogeneous pattern with 61 clusters; based on a 90% agreement. In total, 46 different Hsp60 sequence types were detected. Using 98% sequence similarity, as threshold for separation, 22 separate Hsp60 sequence clusters were distinguished. There was no correlation between H. parasuis serovars and ERIC-PCR clusters or Hsp60 sequence types, but both the ERIC-PCR and the Hsp60 sequence typing are suited as markers for H. parasuis molecular-epidemiology studies. In total, 102 H. parasuis swine isolates corresponded to the virulence associated group 1 vtaA type. The group 1 vtaA was detected in 12 different serovars. Only four of the 46 Hsp60 sequence types were not associated with the group 1 vtaA. This study shows that Dutch H. parasuis isolates from pigs with clinical signs have both a high serovar and genotypic lineage diversity. A majority of the known serovars contain the group 1 vtaA.

Summary Background The aetiology of female pattern hair loss (FPHL) is largely unknown. However, it is hypothesized that FPHL and male pattern baldness (AGA) share common susceptibility alleles. The two major susceptibility loci for AGA are the androgen receptor (AR)/ectodysplasin A2 receptor (EDA2R) locus on the X-chromosome, and a locus on chromosome 20p11, for which no candidate gene has yet been identified. Objectives To examine the role of the AR/EDA2R and 20p11 loci in the development of FPHL using 145 U.K. and 85 German patients with FPHL, 179 U.K. supercontrols and 150 German blood donors. Methods Patients and controls were genotyped for 25 single nucleotide polymorphisms (SNPs) at the AR/EDA2R locus and five SNPs at the 20p11 locus. Results Analysis of the AR/EDA2R locus revealed no significant association in the German sample. However, a nominally significant association for a single SNP (rs1397631) was found in the U.K. sample. Subgroup analysis of the U.K. patients revealed significant association for seven markers in patients with an early onset (P = 0·047 after adjustment for the testing of multiple SNPs by Monte Carlo simulation). No significant association was obtained for the five 20p11 variants, either in the overall samples or in the analysis of subgroups. Conclusions The observed association suggests that the AR/EDA2R locus confers susceptibility to early-onset FHPL. Our results do not implicate the 20p11 locus in the aetiology of FPHL.

Female pattern hair loss (FPHL) is a common disorder with a complex mode of inheritance. Although understanding of its etiopathogenesis is incomplete, an interaction between genetic and hormonal factors is assumed to be important. The involvement of an androgen-dependent pathway and sex steroid hormones is the most likely hypothesis. We therefore selected a total of 21 variants from the steroid-5-alpha-reductase isoforms SRD5A1 and SRD5A2, the sex steroid hormone receptors ESR1, ESR2 (oestrogen receptor) and PGR (progesterone receptor) and genotyped these in a case-control sample of 198 patients (145 UK; 53 German patients) and 329 controls (179 UK; 150 German). None of these variants showed any significant association, either in the overall UK and German samples or in the subgroup analyses. In summary, the present results, while based on a limited selection of gene variants, do not point to the involvement of SRD5A1, SRD5A2, ESR1, ESR2 or PGR in FPHL.

Plasma spray—physical vapor deposition (PS-PVD) is a low pressure plasma spray technology to deposit coatings out of the vapor phase. PS-PVD is a part of the family of new hybrid processes recently developed by Sulzer Metco AG (Switzerland) on the basis of the well-established low pressure plasma spraying (LPPS) technology. Included in this new process family are plasma spray—chemical vapor deposition (PS-CVD) and plasma spray—thin film (PS-TF) processes. In comparison to conventional vacuum plasma spraying and LPPS, these new processes use a high energy plasma gun operated at a work pressure below 2 mbar. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An important new feature of PS-PVD is the possibility to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats, but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional PVD technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and EB-PVD coatings. This paper reports on the progress made at Sulzer Metco to develop functional coatings build up from vapor phase of oxide ceramics and metals.

The production of high quality coatings for fuel cell applications in an industrial scale requires stable, reliable and economically efficient processes. In the recent years, Sulzer Metco has been actively developing coating solutions to fulfill the requirements of fuel cells coating production, in particular for SOFC applications based on both metal and ceramic supported cells. This includes the use of new thermal spray technologies such as LPPS®-Thin Film and TriplexPro{trade mark, serif}-200 to produce the functional layers of fuel cells, such as the electrodes, electrolytes and diffusion barrier layers. In parallel, the development of new powder materials specifically designed towards optimized coating process and functionality has shown an improvement of the cell performance. Both coating technologies have a high potential regarding economical coating production on an industrial large volume scale. This paper presents the current status of developments of the advanced coating technologies together with an overview of the used materials and analysis of the applied coatings.

In order to improve gas turbine performance it is possible to decrease back flow gases in the high temperature combustion region of the turbo machine reducing shroud/rotor gap. Thick and porous TBC systems and composite CoNiCrAlY/Al2O3 coatings made by Air Plasma Spray (APS) and composite NiCrAlY/graphite coatings made by Laser Cladding were studied as possible high temperature abradable seal on shroud. Oxidation and thermal fatigue resistance of the coatings were assessed by means of isothermal and cyclic oxidation tests. Tested CoNiCrAlY/Al2O3 and NiCrAlY/graphite coatings after 1000 hours at 1100°C do not show noticeable microstructural modification. The oxidation resistance of new composite coatings satisfied Original Equipment Manufacturer (OEM) specification. Thick and porous TBC systems passed the thermal fatigue test according to the considered OEM procedures. According to the OEM specification for abradable coatings the hardness evaluation suggests that these kinds of coatings must be used with abrasive tipped blades. Thick and porous TBC coating has shown good abradability using tipped blades.

The production of protective coatings on metallic SOFC interconnects using LaSrMnO (LSM) in an industrial scale requires an economically efficient process in order to obtain high quality and reliable coatings. The TriplexProTM-200 gun is a new advanced plasma spray torch with three electrodes which provides all the features necessary to apply this type of coatings following the requested productivity and quality for a mass production in an Atmospheric Plasma Spray (APS) process. The LPPS-Thin Film technology uses a high power plasma torch operated in a low pressure environment. This low ambient pressure produces a large plasma jet with unconventional properties allowing the production of thin and dense ceramic coatings. Thus, the technology is best suited to deposit very dense electrolyte layers of Yttria Stabilized Zirconia (YSZ) for improved cell performance. Moreover, the large plasma plume in the LPPS-TF process allows a very efficient coating production on large areas.

Measurement of key plasma jet properties, such as the Mach number, electron density and temperature, in a low pressure environment, were performed using double Langmuir probes and Mach probes. In particular, under-expanded jets are studied in detail by performing complete mappings of plasma jet properties at chamber pressures of 10 and 2 mbar. These results show that the measured physical properties are consistent with the jet flow phenomenology, such as the presence of periodic expansion and compression zones, the effect of the pressure and the location of the shocks. It is shown, in particular, that for a highly under-expanded jet at 2 mbar, the Mach number reaches 2.8 in the first expansion zone followed by a strong drop to subsonic flow revealing the presence of a Mach reflection. The flow is accelerated further and a periodic structure of compression/expansion cells is observed until the local static pressure is in equilibrium with the surrounding pressure. These results contribute to the understanding of the supersonic plasma jet behaviour at low pressure and can be used to quantify the deviation from local thermodynamic equilibrium. The extensive mapping of the measured physical properties of the jet will also serve as input for modelling.

This contribution describes the results of impurity seeding experiments using neon gas injection into the private fl zone of an ohmically heated TCV single null lower, deuterium fuelled, open divertor configuration. In these first experiments, neon has been injected under feedback control on the intensity of the UV NeVIII line at 77 nm. Measurements of the dependence of edge temperature and density on ii, at the outboard divertor target show the divertor in the absence of neon to be operating in the low recycling regime. Neon is observed to penetrate easily into the confined plasma at all densities, increasing core radiation and suppressing radiation in the divertor. This suppression is accompanied by reductions of power and particle Bur to the divertor target and D-alpha emission in the divertor volume. The most intense emission is observed in the X-point vicinity and stable discharges have been obtained at radiation fractions, P-R/P-Omega, up to 0.75. Values of (Z(eff))= 1.5-2 and (Delta Z(eff)) = 0.25-0.75 are observed at the highest densities for which the lowest core neon concentrations of approximate to 0.5-1.0% are obtained, with (Z(eff)) appearing to scale with P-R and and (n) over bar(e) according to the empirical relationship derived by Matthews (G.F. Matthews et al., J. Nucl. Mater. 241-243 (1997) 450). There is evidence for an increase in particle confinement when neon is injected, with the effect being most marked at the highest densities when the radiated power fractions are highest. Neon injection is also found to be effective in suppressing ohmic H-modes. (C) 1999 Elsevier Science B.V. All rights reserved.

With increasing fuel prices and significant pressure to reduce emissions, the efficient use of fuels in gas turbines is gaining ever more attention. Abradable seals in gas turbine compressors have contributed to improved efficiencies for quite some time now. To further enhance efficiency, current efforts focus on the seals in one of the hottest sections of the engine, the first turbine stage. Sulzer Metco and GE have designed and tested a new high-pressure turbine abradable seal system in the framework of a European consortium project led by GE Oil & Gas. In the scope of this project, Sulzer Metco developed a novel ceramic coating for application by atmospheric plasma spraying (APS). An engine test verified performance and economic advantages of the new seal system. The measured improvements in engine performance exceed the expected gains as predicted by model calculations.

Different SiC-materials like plasma deposited thin a-SiC:H films, bulk Si doped graphites (SiC30) and pure silicon have been irradiated with an oxygen ion beam of the isotope 18O at energies between 1 and 5 keV and at target temperatures up to 1700 K. The release of oxygen and oxygen containing molecules during irradiation and during subsequent thermal desorption has been analyzed by means of quadrupole mass spectrometry in both the residual gas and direct ‘line-of-sight’ detection. All investigated materials show an enhanced oxygen retention compared to pure graphite and a markedly reduced chemical erosion in the form of CO and CO2 depending on the silicon content of the sample. Furthermore, the oxygen impact onto such substrates gives rise to a build up of a silicon oxide layer at the near surface. This leads to an additional release of SiO during irradiation at elevated temperatures as well as during subsequent thermal desorption.

The sputtering of carbon materials by energetic particles leads mainly to the emission of monoatomic carbon, but also to C2 and C3 clusters. Time-of-flight measurements were performed to determine the energy distributions of C1, C2 and C3 sputtered from graphite during 5 keV Ne+ impact. All energy distributions are characterized by the Thompson distribution with a surface binding energy of 7.5 eV for C, 3.5 eV for C2 and 0.8 eV for C3. Using these distribution data the flux ratios of sputtered C2 and C3 to sputtered C can be determined to be 0.06 for C2/C and 0.03 for C3/C by 5 keV Ar+ impact, 0.05 for C2/C and 0.02 for C3/C by 5 keV Ne+ impact and 0.06 for C2/C and 0.01 for C3/C by 5 keV He+ impact, respectively. Thus, 11% of all sputtered carbon is emitted as C2 and in the case of 5 keV Ar+ impact 9% as C3.

Time-of-flight experiments were performed to determine the energy distributions of various reaction products released from graphite and from B 4 C during 1.5 keV O + impact. CO from graphite is released in two distributions: a thermal energy distribution corresponding to the target temperature and a temperature-independent molecule sputtering distribution which can be fitted by a Thompson distribution with an effective surface binding energy of 0.25 eV. At room temperature, the ratio of sputtered CO to thermally released CO amounts to 0.66. In contrast to this, CO 2 is only released thermally. Various boron oxides (BO, BO 2 , B 2 O 2 , B 2 O 3 ) are released from B 4 C. At room temperature, their energy distributions can be fitted by Thompson distributions with effective surface binding energies between 0.12 and 0.28 eV. With increasing temperature an additional thermal distribution appears. Reaction yields published in previous papers were reevaluated with regard to the energy distributions reported above

The oculocerebrorenal syndrome of Lowe is an X-linked recessive disorder characterized by the triad of congenital cataracts, mental retardation and a renal proximal tubulopathy. Although severity of phenotype might vary, congenital cataracts are part of the definition of this rare disorder. We report a 13-year-old patient with the typical cerebrorenal phenotype of Lowe syndrome, that had remained undiagnosed due to absence of any ocular involvement. OCRL gene analysis was carried. DNA analysis revealed a c.C760T (p.Gln199X) nonsense mutation in exon 8 expected to cause complete disruption of OCRL function. After sequencing the parents of the index patient and his maternal grandparents, this mutation turned out to be de novo in the mother. Furthermore, a silent variant (p.Arg35=) was identified in exon 2, that could also be identified in the mother and her 3 sisters, but not in the grandparents assuming germ cell mosaicism in either of the grandparents. RNA analysis from the patient’s lymphocytes revealed presence of full-length OCRL transcripts. Western blotting from lymphocyte samples failed to detect OCRL protein even in controls. Our findings extend the phenotypic spectrum caused by OCRL mutations and illustrate that there may be selective organ involvement in Lowe syndrome.

The aetiology of female pattern hair loss (FPHL) is largely unknown. However, it is hypothesized that FPHL and male pattern baldness (AGA) share common susceptibility alleles. The two major susceptibility loci for AGA are the androgen receptor (AR)/ectodysplasin A2 receptor (EDA2R) locus on the X-chromosome, and a locus on chromosome 20p11, for which no candidate gene has yet been identified.To examine the role of the AR/EDA2R and 20p11 loci in the development of FPHL using 145 U.K. and 85 German patients with FPHL, 179 U.K. supercontrols and 150 German blood donors.Patients and controls were genotyped for 25 single nucleotide polymorphisms (SNPs) at the AR/EDA2R locus and five SNPs at the 20p11 locus.Analysis of the AR/EDA2R locus revealed no significant association in the German sample. However, a nominally significant association for a single SNP (rs1397631) was found in the U.K. sample. Subgroup analysis of the U.K. patients revealed significant association for seven markers in patients with an early onset (P = 0·047 after adjustment for the testing of multiple SNPs by Monte Carlo simulation). No significant association was obtained for the five 20p11 variants, either in the overall samples or in the analysis of subgroups.The observed association suggests that the AR/EDA2R locus confers susceptibility to early-onset FHPL. Our results do not implicate the 20p11 locus in the aetiology of FPHL.

Summary Background Isolated nail dysplasia is rare and has been reported in only a small number of families. Objectives To describe and characterize two Pakistani families with an autosomal-recessive inherited nail dysplasia. Methods Genome-wide linkage analysis; mutation screening of candidate genes by Sanger sequencing; cloning of FZD6 and protein analyses; immunohistochemistry. Results We mapped this genodermatosis to chromosome 8q22.3, and identified a homozygous nonsense mutation c.1750G>T (p.E584X) in the frizzled 6 (FZD6) gene in all affected individuals. Immunohistochemical analyses in nail sections from healthy individuals revealed strong expression of FZD6 in the ventral nail matrix and a less pronounced expression of FZD6 in the nail bed. Conclusions FZD6 belongs to a family of proteins that serve as receptors in Wnt signalling pathways, and has been shown to act as a negative regulator of the canonical Wnt/β-catenin signalling cascade and a positive regulator of the noncanonical Wnt or planar cell polarity pathway. The present results therefore suggest that FZD6 plays a pivotal role in the growth and guidance of the nail plate in humans by acting as a molecular switch between different Wnt pathways. Previous studies have identified mutations in the RSPO4 and LMX1B components of the Wnt pathway in patients with the hypoplastic nail disorders anonychia and nail-patella syndrome, respectively. Only recently, FZD6 mutations were identified in isolated nail dysplasia. The present results emphasize the important role of the Wnt pathways in nail development and increase understanding of Wnt-mediated developmental events in general.

Pure graphite (EK 98), boron-doped graphite (3%B, 15%B, 20%B), thin boron/carbon layers (a-C/B:H films) and B4C were irradiated with energetic oxygen ions of 1–5 keV to study the erosion and retention behaviour of energetic oxygen. The reaction of O+ ions with these materials lead mainly to the formation of volatile CO and CO2 together with physically sputtered carbon, boron and boron oxide species. Compared with graphite, the retention of oxygen in the boron/carbon materials is higher and the reemission of CO and CO2 in delayed after starting the bombardment. The thermal desorption of the implanted oxygen in form of CO occurs in addition to the normal CO peak at 950 K in a second peak at about 1600 K. At these high temperatures also BO, B2O2 and B2O3 (peaked between 1200 K and 1400 K) are desorbed.

Summary Background Congenital atrichia is a rare autosomal recessive form of isolated alopecia which is caused by mutations in the human hairless (HR) gene. Patients are born with normal hair that is shed almost completely and irreversibly during the first weeks of life. Objectives To investigate the molecular genetic basis of congenital atrichia in two patients, and to analyse the functional consequences of one newly identified and all seven previously identified HR splice site mutations using a minigene assay. Methods Molecular analysis of the HR gene was performed by direct DNA sequencing. To analyse the functional consequences of the splice site mutations, the respective sequences were cloned into a vector which allows directed splicing. After transfection of COS7 cells, isolation of RNA and cDNA synthesis, sequencing was performed to analyse the products. Results Two novel mutations were identified: an insertion in exon 2 (c.485insT; p.C162LfsX17), and a splice site mutation (c.2847–1G>A). In vitro analysis revealed aberrant splicing for all eight of the investigated HR splice site mutations. Comparison with the results of two biocomputational programs (neural network splice server and CRYP-SKIP) and calculation of consensus values revealed that the predictions of these two programs were consistent in only five and two of the eight mutations, respectively. Conclusions This is the first report to analyse the consequences of HR splice site mutations using a cell-based in vitro assay. The results highlight the importance of performing splicing experiments to clarify the consequences of putative splice site mutations.

Una strategia per l’incremento delle prestazioni delle turbine a gas consiste nella riduzione del trafilamentodei gas nella zona ad alta temperatura della turbomacchina grazie alla riduzione della distanza tra lasommità delle palette e la copertura protettiva della cassa della turbina. A tal fine sono stati studiati sistemiabradibili realizzati mediante diverse tecniche. Sono stati realizzati sistemi compositi compositi a baseCoNiCrAlY/Al2O3 mediante tecnica Air Plasma Spray (APS), a base NiCrAlY/graphite mediante tecnica LaserCladding e barriere termiche spesse e porose. Le resistenze all’ossidazione e alla fatica termica dei rivestimentisono state valutate per mezzo di prove di ossidazione isoterma e ciclica. I rivestimenti compositiCoNiCrAlY/Al2O3 e NiCrAlY/graphite dopo 1000 ore a 1100°C non hanno mostrato rilevanti modificazionimicrostrutturali. La resistenza all’ossidazione dei nuovi rivestimenti compositi soddisfa le specifiche deiproduttori, gli “Original Equipment Manufacturer” (OEM). Le barriere termiche spesse e porose superano i testdi fatica termica imposti dalle procedure degli OEM. La durezza di tali rivestimenti suggerisce il loro uso incombinazione con palette dotate di rivestimento abrasivo sull’estremità. Le barriere termiche hanno mostratobuone caratteristiche di abradibilità.

In the present study we report the clinical features and the molecular genetic investigation of the tyrosine aminotransferase (TAT) gene in a young girl from Croatia with Richner-Hanhart syndrome, mainly suffering from photophobia, hyperkeratosis of the palmes and soles and slight neurological abnormalities. Sequencing analysis of the TAT gene revealed a novel homozygous missense mutation c.1250G>A (p.R417Q) in exon 12, and herewith confirmed the clinical diagnosis. Showing the first symptoms in babyhood, at the age of 8 years it was for the first time clinically diagnosed that the patient suffers from tyrosinemia type II and a therapy with tyrosine and phenylalanine reduced diet has been started successfully. All symptoms disappeared within 2-4 weeks. Since that time, we have been following the girl until today for more than ten years. She is in a good condition, and attends the normal high school program.

Background In 1925, Dr Marie Unna described a rare form of hereditary hypotrichosis in a German multigenerational family. This was later termed "Marie Unna hereditary hypotrichosis" (MUHH). MUHH is an autosomal dominant disorder that is characterized by the absence or scarcity of scalp hair, eyebrows, and eyelashes at birth; coarse and wiry hair during childhood; and progressive hair loss beginning around puberty. Causal mutations in U2HR, an inhibitory upstream open reading frame in the 5'-untranslated region of the human hairless (HR) gene, were recently identified in several unrelated MUHH families from various ethnic backgrounds. Objective Although there have been several clinical reports of descendants of the originally described family, the molecular cause of disease in this particular family has not been established. The aim of this study was to investigate descendants of this family and to analyze their DNA for the presence of U2HR mutations. Methods Descendants of the family (including one affected individual) were examined clinically. Direct sequencing of U2HR was performed. Enzymatic digestion using the restriction enzyme NcoI was performed to confirm the sequencing results. Results The index patient displayed the typical MUHH pattern of hair loss and was found to carry the disease-causing c.3G>A (p.M1I) U2HR mutation. This mutation was not detected in unaffected family members. Limitations Only one affected family member was investigated. Conclusions Eighty-five years after the first description of this rare form of alopecia, the disease-causing mutation in the originally reported family has been identified.

This work shows that low-pressure plasma spraying equipment can be used to deposit layers of varying thickness from liquid or gaseous precursors. In particular, HMDSO and oxygen are used to deposit SiOx thin films over large areas at deposition rates exceeding 35 nm/s and conversion efficiency better than 50%. The coatings are analyzed ex-situ by FTIR absorption spectroscopy and the microstructure and morphology of layer cross-sections are examined by SEM. The effects of various process parameters are investigated as well.

Low-pressure plasma spray thin film (LPPS-TF) is a recently developed vacuum plasma spray technology that makes it possible to deposit coatings not only by melting feedstock material, but also by vaporizing injected particles. This capability fills a gap between conventional vapor deposition and thermal spray processes. The vaporizing of coating material and formation of layers out of the vapor phase result in unique coating microstructures with superior properties. This paper reports on the progress made in the development of functional coatings built up from the vapor phase of metal and oxide ceramics.

Reliable and economically efficient processes are necessary for the production of high quality coatings for solid oxide fuel cells (SOFC) applications in an industrial scale. In that perspective, Sulzer Metco developed several coating solutions through different processes adapted for each specific applications, in particular on metal supported cells (MSC). Diffusion barrier layers (DBL) using perovskite material, such as Lanthanum Strontium Manganite (LSM), is produced “state-of-the-art” as coating service by Sulzer Metco on metallic interconnects (IC) using the Triplex technology. The newly developed TriplexPro-200 having a long lifetime performance and specific features, like cascaded arc and 3-cathode torch, is the best candidate for producing high quality and reliable coatings in a mass production of SOFC functional layers. LPPS-Thin Film, on the other hand is the technology of choice to deposit very dense, thin and homogeneous layers on various substrates. Yttria stabilized Zirconia (YSZ) layers of 20-40 µm thickness have been deposited on thin metallic substrates (0.7 mm, 140 cm2) without producing any strong deformation of the substrate. Considering the dimension of the metallic substrate the coated cells present very good gas leak tightness performances between 2 and 8 Pa·m/s which is homogeneous on the substrate area. Moreover, LPPS-TF can also be used to produce very dense and thin LSM coatings on interconnects. In this case, LPPS-TF not only produces denser and thinner coatings but also becomes again competitive when considering the manufacturing of DBL for metallic ICs on a high production scale. This paper presents the current developments of these technologies in the domain of SOFC applications.

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LPPS-Thin Film is a vacuum plasma spray technology recently developed by Sulzer Metco. In comparison to conventional Vacuum Plasma Spraying (VPS) or Low Pressure Plasma Spraying (LPPS), LPPS-Thin Film uses a working pressure below 2 mbar and a high energy plasma gun. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An additional new feature of LPPS-Thin Film is the possibility to deposit a coating not only from liquid splats by melting the feed stock material but also from gas phase by vaporizing the injected material. The coatings produced from vapor phase show similar structures to EB-PVD layers. The coating thickness can vary from only a few microns up to more than 300 μm. The LPPS-Thin Film process fills the gap between conventional PVD/CVD technologies (≤ 1–5 μm) and standard thermal spray processes (≥ 50 μm). However the concept of “Thin-Film” not only refers to the thickness of the coating. In particular the vaporizing of ceramic coating material also enables new layer properties in a domain between thermal spray and EB-PVD. Yttria Stabilized Zirconia (YSZ) can be deposited with a columnar microstructure. Lab investigations show that these coatings have potential for lower thermal conductivity and higher thermal stress tolerance compared to standard EB-PVD layers.Copyright © 2008 by ASME

Abradable seals have been used in jet engines since the late 1960's. Today abradable seals are seeing applications not only in low pressure and high pressure sections of the compressor but also in the high pressure turbine module of jet engines and are gaining ever more attention in industrial gas turbines. Thermal spraying is a relative simple and cost effective means to apply abradable seals. These work by minimizing gaps between rotating and stationary components by allowing the rotating parts to cut into the stationary ones. The types of coatings employed are zirconia based abradable material systems with polymer and, in some cases, hexagonal boron nitride additions. The coatings are designed to work at service temperatures of up to 1200 °C. The objective of this paper is to review various types of commercial and experimental ceramic abradable systems and to assess their performance profiles. The paper will review yttria stabilized zirconia based systems with modified polymer additions and with variable particle sizes of the ceramic phase. Alternative stabilizers and their influence on key coating properties such as thermal shock resistance and abradability will be studied. The paper will also review the influence of plasma spray parameters on coating properties and study the general influence of coating porosity on coating erosion properties and abradability.

With the new development of the LPPS Thin-Film technology (LPPS-TF), which is a special modification of conventional LPPS using reduced chamber pressures below 10 mbar, a new window has been opened to deposit uniform and dense thin layers onto large areas in short coating times. This spray process will allow the access to new market areas and will be able to bridge the gap between conventional thin film (< 1 - 10 µm) deposition using PVD/CVD processes and thick (> 50 - 200 µm) thermally sprayed layers. This paper presents the status of the LPPS-Thin Film technology as a hybrid coating process between thermal spray and vapor deposition and gives an overview of potential applications for functional thin coatings and large area coverage.

Low pressure plasma spraying (LPPS) and LPPS-Thin Film (LPPS-TF) processes cover a broad operational pressure range from typically 200 mbar down to a few millibars, filling the gap between conventional thermal spray processes, where coatings are made from the liquid phase, and conventional thin film technologies such as PVD or CVD, where coatings are produced from precursors species in the vapor phase. Using some specific parameters of the LPPS-TF process, the injected material can be partially or even completely in gaseous phase, disqualifying diagnostics based on the detection of solid or liquid particles such as the DPV-2000 (Tecnar, St-Bruno, QC, CA). In this case, other optical diagnostic tools have to be used, such as optical emission spectroscopy (OES) to characterize the LPPS-TF process. In this paper, a qualitative study of the properties of the injected material in the plasma jet using DPV-2000 and optical emission spectroscopy is presented by varying specific plasma parameters. Moreover, in some particular cases, it is shown that the combination of DPV measurements and OES can help to monitor the coating process and to improve the basic understanding of the LPPSTF technology.

Low pressure plasma spraying (LPPS) is well established as coating process for the deposition of TBC systems for industrial gas turbines as well as aero applications under industrial standards. With the extension to LPPS Thin Film process, the operating conditions can vary in a wide range from only a few mbar up to typically 200 mbar which imposes different characteristics of the corresponding spray conditions and resulting coating properties. The flexibility of this process allows for subsequent coating of different layers for bond and top coat of a complex TBC system by using only a single TS technology. This simplifies the operational needs for industrial production and offers the potential of increased technological and economical benefits. Depending on the process conditions a broad variety of different TBC layers, multi-layer systems including bond coats & diffusion barriers, dense, porous or graded YSZ layers as well as EB-PVD like layers with columnar microstructure, can be realized using the LPPS-TF technology. Proper adjustment of spraying conditions and suited material selection allows controlling the grade of “columnarity” of the layer. Thermal cycling as well as GE erosion tests have been used to characterize and benchmark the coating quality. Transfer of such coatings onto real turbine blade has demonstrated that all substrate areas could be coated with a columnar TBC structure up to a thickness of about 250 microns. This offers the possibility either to develop coatings with optimized performance or of comparable quality at reduced production costs when compared to established vapour deposition techniques like EB-PVD. This paper presents an overview on the development of various TBC systems such as multi-layers or columnar structures by using the LPPS Thin Film technology.

In the thermal spray industry there remains a constant demand for more stable, controllable and economical processing devices. Most thermal spray applicators apply a wide range of materials especially those who are allied with the turbine markets. Each material coating specification requires a relatively specific range of velocity and temperature transferred to the powder particle to achieve the required material properties on the part. The plasma gun has become a dominant process tool in the turbine industry due to the wide range of parameters that are achievable with the basic tool. In addition, there are today a large number of individual plasma guns that are each known to provide excellent results with some, but not all coating requirements. In many cases the optimum gun running condition can never be achieved due to the interdependence of arc behavior and gas conditions. The turbine industry is currently largely populated with guns that are based on the technology as it was developed in the 1960’s. These guns are characterized by poor voltage stability with a large quasi periodic oscillation in the 3-5 kHz range as described by Bisson [1], with poor performance and life under more extreme operating conditions. A key element of any plasma gun is the nozzle geometry. The cascaded gun types as typified by the Triplex offer a unique opportunity to study and document a wide range of operational parameters, especially at extreme operating conditions.

Plasma spraying at low pressure conditions (LPPS) is a well established thermal spray process with a broad variety of important applications in different industrial segments. The operating conditions for LPPS processes can vary in a wide range from only a few mbar up to typically 200 mbar which imposes different characteristics of the corresponding spray conditions and resulting coating properties. Thermal spray processes have been approved being suitable for integrated fabrication of various layers for SOFC components. Depending on the process conditions, different layers used as functional coatings of SOFC components such as dense electrolyte layers as well as porous electrodes can be realized using the LPPS technology. Due to the flexibility of these processes, an optimized performance of the application on different target materials and geometries is possible with an increased technological and economical benefit compared to conventional thermal spray techniques. This paper presents an overview on the general potential and spray conditions of the LPPS process and its application for the deposition of various functional layers such as electrolyte and electrodes for SOFC components.

This paper provides an overview of the tools and techniques used in industry to monitor and control plasma spraying processes. It describes how the tools work and what they can reveal about spraying processes and coating properties. It also presents examples showing how the tools are used to optimize spray parameters for special applications and discusses the possibility of implementing closed loop control for plasma spraying processes. Paper includes a German-language abstract.