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High temperature plasma coating technology has been applied to recover damaged aluminum dies from wear by spraying pure aluminum and alumina powder. However, the coated mixed powder layer composed of aluminum and alumina often undergoes a detachment from the substrate, making the coated substrate die unable to maintain its expected life span. In this study, in order to increase the bonding strength between the substrate and the coating layer, a pure aluminum layer was applied as an intermediate bond layer. In order to prepare the specimen with variable bond coating conditions, the bond coat layers with a various gun speed from 10 cm/sec to 30 cm/sec were prepared with coating cycle variations ranging from three to nine cycles. The specimen with a bond coat layer coated with a gun speed of 20 cm/sec and three coating cycles exhibited ~13MPa of adhesion strength, while the specimen without a bond coat layer showed ~6 MPa of adhesion strength. The adhesion strength with a variation of bond coat layer thickness is discussed in terms of coating parameters.

It is established that a promising method for surface strengthening of plasma coatings is diffusion chromizing. Chromizing of a plasma-deposited iron layer increases its density, cohesion with the base, and wear resistance under friction conditions without a lubricant.

The results of investigations and development of production technology of low temperature resistance heaters by means of coating are presented. An arc plasma generator with inter-electrode insertion (IEI) for coating resistance and insulating layers is described. Some peculiarities of plasma coating technology for flat resistance heaters production are considered.

Stainless-steel powder was coated on mild steel substrates using a plasma coating technique. The porous coating thus obtained was modified using laser treatment. The oxidation behaviour of the plasma-coated as well as the laser-treated materials was studied in air at 1073 K. The oxidation rate decreased considerably after plasma coating compared with the stainless steel as expected, but there was a further significant improvement in the oxidation resistance after laser treatment of the coated surface. The adherence of the scale, tested using an acoustic emission technique and thermal cycling showed significant improvement.

Stainless Steels are required for many applications for ship building as well as for offshore structures such as oil exploration. AISI type 304 stainless steel is not very suitable for such applications as it has a strong tendency for pitting and crevice corrosion. Even type 316 and 317 stainless steels which have respectively 2.5 and 3.5% Mo are not very effective in these environments. Commercially available stainless steels, viz., Avesta 254 SMO is being employed for such applications because of its strong resistance to pitting and crevice corrosion. This is mainly because of high Mo concentration (6.5%). Such steels are not only costly but are prone to form deleterious phases such as delta ferrite and sigma during welding or other heat treatment operations. Hence, an alternative technique to restrict Mo at the surface is needed. In the present work, surface alloys consisting of an austenitic stainless steel with Mo content as high as 10-12% have been formed on stainless steel type 304 substrates. These steels show enhanced passivity and strong resistance to pitting corrosion.

Up to now, a pulsed plasma with pulse rates between 50 and 150 kHz has been used in PVD techniques only rarely. Recently, our activities and the efforts of various other research teams were concentrated on this field. The MF-pulsed plasma offers facility to overcome limitations that restrict the use of DC and RF sputtering. A high motivation for further development results from the objective to coat large areas, to attain the highest possible deposition rates and to carry out a considerate plasma-assisted surface treatment or plasma coating matched to the compatibility of the substrates. Via pulsed sputtering and plasma-activated deposition, the application of a pulsed plasma goes from tasks of substrate pretreatment and etching to the plasma-assisted surface treatment of layers or workpieces. Unipolar pulsed electrodes — in particular floating-powered multi-electrode arrangements — pave the way to stable long-term and arc-free reactive deposition of defect-free and electrically insulating layers. The pulsed plasma also opens up fresh ground in the use of bias effects for the deposition of poorly conducting layers and for the coating of thin insulating substrates on an industrial scale.

We have evaluated by different coating methods (plasma coating, high-velocity flame-coating) in vivo one year after implantation. 1. Thickness of Coated HA: The thickness decreased compared with the initial values. However, there were no significant intergroup difference in thickness. The minimum thickness was O μm in each group. 2. Biological Findings: Basically, there were no biological differences; sprayed HA come into direct contact with bone without fibrous tissues.

In a variety of industrial area, hard face applications are mostly required. In order to obtain high surface hardness, there are many methods, namely plasma coating, PVD, CVD, thermochemical treatments, etc. Among the methods, boriding can be very effective and economic. This process is simply diffusion of boron into steel. The most important aim of the present work is to obtain high surface hardness. In this study, X210Cr12 (D3) steel has been borided in four different boriding baths, and cooled in oil and air mediums. As a result, 90-100 μm boride layer, and 1600-2000 HV surface hardness have been obtained on the steel surface.

Polycarbonate makers General Electric and Bayer have signed a letter of intent to form a 50-50 joint venture that will accelerate the two companies' separate efforts to replace glass automobile windows with plastic. The two corporate giants see a window of opportunity in the $6 billion worldwide market for automotive glazing if they can improve the abrasion resistance of polycarbonate. Improving coatings technology is key to improving polycarbonate's scratch resistance, says Mark Whitman, direaor of plastics technology at Bayer and soon to be the new venture's vice president of technology. The partners will work on coatings technology such as GE's inorganic plasma coating and a Bayer technique to embed microscopic ceramic particles in an elastomeric siloxane coating. The two partners plan a collective investment of $40 million over the next few years in coatings technology and advanced manufacturing techniques. About 60 staffers from GE and Bayer will initially join the new venture company, ...

Electromagnetic shielding behaviour of plasma-sprayed Y1Ba2Cu3O7-x coatings has been studied in the frequency range of 1 to 100 kHz. Experiments with 180 μm thick coatings on stainless-steel substrates have shown that the normal-to-superconducting phase transition introduces an additional 15 to 20 db shielding.

A technique for accelerating the development of tissue layers on fabrics implanted in the bloodstream has been explored in dogs and monkeys. Endothelial cell seeding of the fabrics with cells derived from the endocardial surface of the atrium together with an autogenous plasma coating was shown to accelerate organization of fabric-covered devices implanted in the bloodstream of adult primates. At the same time, this technique appears simple and rapid enough to be practical in a clinical setting. The results suggest that this approach might be useful in accelerating the development of tissue layers on prosthetic valves implanted in the heart.

In the case of implant in the field of dentistry it is considered ideal to make the shape as simple as possible and further to obtain implant materials having the same function as natural teeth and healthy teeth. In order to obtain an artificial root of teeth, what should first be considered is the method of combined fixation between the artificial root of teeth and in vivo bon tissue. The key for this question is to make the surface of the root of teeth porous. Recently coating has frequently been selected as a way making the surface of the artificial root of teeth porous. The reason for application of coating is first that porous film is obtained simply and therefore the surface area is increased, leading to simplification in the shape of implant. At present the artificial root of teeth that ultramicroparticles of titanium is plasma coated to titanium material is used clinically. In Japan I000 cases have already been reported. When compared with the hitherto artificial root of teeth, the operative procedure is systematized and bone plantation is stout.

The paper analyzes the conditions for the formation of a coating obtained using an electrothermal axial plasma accelerator due to plasma transfer of cathode erosion products. It is shown that by using a cathode of low-melting materials with a high-current pulsed discharge, microdrops are formed and injected from the accelerator falling into the surface to be treated. When colliding with the surface, the drops acquire near-disk shape with a radius of up to 100 μm, cooling on the substrate at a speed of up to 108 K/s. This leads to the formation in the drops of a supersatu-rated solid solution with nonequilibrium structure. The subsequent heat treatment of the coating can result in harden-ing phases precipitation from solid solution causing the increase in coating microhardness.

Radio frequency (RF) induction heating is used in order to generate thermal waves in conducting materials. This technique is applied to measure the thickness of tungsten-carbide plasma coating on stainless-steel plates. The letter briefly discusses major advantages and disadvantages of RF induction heating.