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The jaw coupling with a flexible spacer is frequently used in the torque transmission between shafts with misalignment for machinery. Its torsional stiffness and limit torque closely determine the operational capacity and the dynamic characteristics of the system because the coupling is usually the most flexible link in the driving chain. In this study, the optimal design of a jaw coupling with an elastomeric spacer was investigated using the Taguchi method by considering four design factors: the tightening method of the clamping bolts, the tightening torque of the clamping bolts, the hardness of the thermoplastic polyether ester elastomer spacer and the installation angle between the two end blocks of the coupling. All specimens were tested by using an in-house torsion tester to record the torque-angular deformation responses. The results showed good reliability and repeatability, with a coefficient of variance within 5%. Spacer's hardness was found to be the most significant factor regarding the torsional stiffness, while the magnitude of the clamping torque had the most critical role in the limit torque. The estimation formulae for the torsional stiffness and limit torque of the jaw coupling were obtained by using the statistical regression of the measured data, respectively. Both formulae predicted the performance of the optimal designs within 5% of error compared to the confirmation tests.

Locknut is a critical component used in the precision machinery and its stable service performance over a long period of time in a variety of different environments presents a crucial challenge. In this study, a flank-locking precision locknut was pretreated in an immersion corrosion of 5 wt% NaCl solution to simulate the possible corrosion effects. The tightening and loosening of the locknut after 0-, 1-, 2- and 4-h corrosion treatments, respectively, was tested according to the ISO 2320 Standard. An in-house test setup with horizontal configuration was employed in measuring the torque–axial force characteristics under loading–unloading cycles. It was found that the corrosion of the locknut accelerated after 1-h immersion. The corroded specimens after 2- and 4-h treatment demonstrated more variance in measured tightening and loosening torques than their less corroded counterparts. However, after five loading–unloading cycles, the variance in measured torque decreased and the associated torque constants became more stable. Moreover, the torque constants were ∼10% higher for the 2- and 4-h corrosion-treated locknuts than their pristine counterpart. The surface morphology after corrosion and friction wear was closely related to the measured testing results.

The influence of combined corrosion and vibration to the anti-loosening performance of a precision locknut used in a machine tool is investigated. Firstly, the locknut was submerged in 5% NaCl solution according to ASTM B895 standard for corrosion testing. The locknuts, after submerged in 1-hr, 2-hr and 4-hr periods, respectively, were then installed on the rotating spindle in a vertical dynamic impact tester for performing anti-loosening test. The initial installed pretension was 9800 N and the spindle was rotating in a constant speed of 1000 rpm. Turmogrease Li 802 EP lubricant was used on the contact surface between spindle thread and locknut. The set screws on the locknut were tightened sequentially and evenly in three-stage of torque: 1.96 N-m, 3.92 N-m and 5.88 N-m. Its real-time pretension variation with the periodic transverse impact and its final loosening torque were measured. Accordingly, the axial force ratio and anti-loosening torque ratio were calculated and discussed. It was found that corrosion treatment had similar influence on both the axial force ratio and the anti-loosening torque ratio. More corrosion on the locknut with longer submersion in NaCl solution deteriorated its anti-loosening characteristics. The result could serve as the reference for evaluating the fastening performance of precision locknut and guide the design and manufacturing for the application improvement.

In this study, the anti-loosening characteristics of a precision flank-locking locknut fabricated under various machining processes and tested in different dynamic environments were investigated. The control parameters considered include the tightening torque and thread pitch of the set screw, machining process on the end plane of locknut, and vibration amplitude and frequency of dynamic loading in service, etc. Their sensitivities on the axial force ratio and anti-loosening ratio of the locknut were evaluated using Taguchi method. It was found that the pretension of locknut, the tightening torque and the pitch of set screw, and the machining process of the nut's end plane were the significant control parameters for the anti-loosening performance of the locknut. Moreover, the results of experimental measurements were employed in the regression fit on the performance of the locknut. The regression model was able to predict the anti-loosening ratio with 4.42% average error comparing with the measurements. Furthermore, the optimized design of the locknut through the Taguchi method was able to increase the axial force ratio and anti-loosening ratio by 20.4% and 16.8%, respectively, comparing with standard locknut.

In this study, zinc anodes used in Zn-air battery were fabricated by electroplating processes, i.e., conventional direct current (DC) electroplating and pulse plating. The results showed that the surface morphology of zinc prepared by the electroplating process was porous in contrast to the commercial bulk zinc (BZn). The power density of batteries consisting of electroplated Zn anodes were increased comparing with their bulk counterpart. Moreover, because the anode with high specific surface area can reduce the distributed current density and inhibit the passivation that may block oxidization of active material during discharge, the utilization of anode material can be improved without other treatments. Among the fabricated anodes, the one prepared by pulse plating with frequency of 500 Hz showed the best battery performance. The specific discharge capacity and battery efficiency reached 711 mAh g− 1 and 86.7%, respectively. The result indicated a 50% improvement with respect to BZn. The highest peak power density of the pulse plated Zn anode achieved 23.4 mW cm− 2 at room temperature. Comparing with other recent zinc-air battery studies using MnO2-based air cathode, the discharging power density of this zinc anode prepared by pulse electroplating with frequency of 500 Hz showed a 15% improvement.

Tunable vibration absorber is an effective device to reduce the vibration of structure subjected to harmonic excitation. The vibration energy is transferred mostly to the absorber when the natural frequency of the absorber is tuned to the excitation frequency. In this study, a piezoelectric (PZT) transducer was incorporated into the absorber in order to harvest the vibration energy and still alleviate the vibration of a platform structure. The tuning in dynamic characteristics of the absorber was facilitated by controlling its tip mass. The design formulation of the absorber was presented with a single degree-of-freedom (SDOF) model having the equivalent parameters. In the meantime, an optimal electric load resistor was determined to maximize the power output from the PZT transducer. The experimental measurement validated the SDOF model with good accuracy both in the vibration response and the output electric voltage. Finally, the absorber was installed on a platform structure to investigate its vibration reduction and energy harvesting capability for the external disturbance frequency covering certain frequency span. With three resonance modes of the platform studied, the absorber was able to reduce more than 80% of its original vibration and harvest several folds of electric power comparing with the untuned absorber. Although the performance in vibration reduction was slightly influenced (

Amorphous alloys owing to their high hardness, strength, corrosion and wear resistance are regarded as one of the potential coating materials for applications in severely corrosive environment. A high-velocity‑oxygen-fuel (HVOF) spraying process was employed in this study to prepare an amorphous Fe alloy coating on SUS316 substrate. The prepared Fe40-Cr19-Mo18-C15-B8 alloys had high hardness but the micro-structural examination showed micro-voids and micro-cracks permeated in the coating. Both x-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements confirmed the combined amorphous and nano-crystalline phases in the coating. Thermal stress after cooling from the spray process caused the emergence of intensive cracking. The potentio-dynamic polarization curves of the prepared coating were measured in four different solutions, respectively: 0.5 M H2SO4, 1 M NaOH, 3.5 wt% NaCl, and seawater. Among them, the prepared coating had better corrosion resistance in neutral solutions. The corrosion tests under different applied over-potentials in seawater further revealed nearly ten-fold increase in corrosion current when the over-potential was raised from −100 mVSCE, +200 mVSCE, +600 mVSCE, to +800 mVSCE, respectively. Although the coating surface roughened considerably at higher over-potentials, oxidation of Mo and Cr elements in this Fe alloy during corrosion test, confirmed from the measured six-valenced ions of Mo6+ and Cr6+ in the x-ray photoelectron spectroscopy (XPS) analysis, was beneficial in lowering the corrosion current.

The corrosion resistance of electroplated Zn–Ni alloy using trivalent chromium conversion treatment in alkaline electrolyte was investigated. Among the Zn–Ni coatings electroplated on steel substrate with raising current densities, the Ni content and corrosion resistance increased accordingly. Further conversion treatment generated passivates which thickness increased with treatment durations. The passivation film showed Ni rich content comparing with its pristine Zn–Ni coating and mainly composed of Cr2O3, ZnO and NiO. The passivation film improved corrosion resistance. However, the 30-s treated specimen showed best corrosion resistance because of its moderate thickness and less dehydration voids and cracking in the passivation film.

With the high density and high precision requirement of electronic products, printed circuit boards (PCBs) are also facing the evolution into multilayer boards. Electroless nickel immersion gold (ENIG) is a process that is widely used in the surface treatment of PCBs. As a barrier layer, nickel plating is required even in the blind via of PCB to improve its corrosion resistance for further plating processes. In this study, different surfactants, mainly anionic surfactant, Sodium Dodecyl Sulfate (SDS) and cationic surfactant, Cetyl Trimethyl Ammonium Bromide (CTAB), are used to explore their possible effects on this electroless process. It is found that SDS improves the deposition rate in blind via plating and coating's surface roughness. The surfactants are also effective in increasing the corrosion resistance of the prepared coating. Furthermore, different plating processes, i.e. supercritical carbon dioxide (Sc-CO2) assisted electroless plating and post supercritical carbon dioxide assisted electroless plating, are investigated and compared with the conventional process. It is obtained that Sc-CO2 assisted plating has the best improvement in blind via deposition rate and better coating's corrosion resistance. The result is indebted to the fact that the bath mixed with Sc-CO2 has low surface tension of gas and high mass transfusion of liquid. This nature effectively increases the deposition rate of coating in the blind via, and also makes the surface of the coating smoother and more uniform. To further explore whether high temperature affects the corrosion resistance of the coating when it passes through the reflow oven in surface mount technology (SMT) soldering operations of PCB, the coating is annealed at different elevated temperatures up to 400 °C. The experimental results found that annealing enables the grain refinement of the plated layer, thereby enhances the corrosion resistance of the plated layer.

A new design of tuned mass damper was proposed in this study to reduce the structural vibration of a machine platform subjected to varying excitation frequency, e.g. disturbance from the unbalance mass of motor in different rotational speeds. The absorber mass was changed by pumping of fluid between the liquid chambers of the vibration absorber. With the stiffness remained unchanged, the absorber׳s natural frequency could be tuned accordingly. Thus, reduction in machine vibration could be obtained by tuning the natural frequency of the absorber according to the frequency of external harmonic disturbance. Firstly, the variations of natural frequency and damping ratio of the absorber with different tuned masses were measured experimentally. The natural frequency results showed that the adjustable ranges for the first two modes could all reach more than 30%. Then, the absorber was installed on a machine platform and its performance was investigated under external disturbance at the natural frequency of the platform. It was found that, due to the effect of damping increase originated from the fluid sloshing inside liquid chamber, the vibration reduction effect from the absorber was limited. To improve this situation, we added a horizontal separation panel inside the liquid chambers, and the experimental results showed that the liquid sloshing was alleviated, and effectively reduced the damping ratio of absorber. Thus, the system became more stable and the control efficiency was effectively improved.

The nickel films with nano-sized grains, high hardness and smooth surface have been prepared using a new electroplating technique involving the post supercritical mixed electrolyte. After mixing watts bath with Sc-CO 2 , the pH value of exposed electrolyte got lower but then raised backward gradually. The released CO 2 concentration from this Sc-CO 2 mixture has also been evaluated within 3 h of agitation. As the plating result, average grain size of the 20 μm-thick coatings were 16, 34, and 210 nm for those plated from pure Sc-CO 2 , post Sc-CO 2 and conventional method, respectively. Evaluated on the cross section, microhardness of a 100 μm-thick post Sc-CO 2 nickel coating has reached 650 Hv within the regions below 50 μm from the substrate interface then decreased to 350 Hv on further away regions. The high hardness region of nickel coating was found closely related to the electrodeposited duration when electrolyte still possessed high CO 2 concentration. Moreover, the incorporation of carbon in nickel electrodeposit was found not only at the pure Sc-CO 2 coating but also at the post Sc-CO 2 one. Therefore, this new plating technique not only confirms the roles of dissolved CO 2 bubbles in electrolyte but also provides a potential to overcome most issues associated with the cost in building high-pressure environment for large size products and continuous plating using supercritical method.

In this study, the internal stress of Ni coating electroplated in the supercritical-CO2 (Sc-CO2) mixed Watts bath was investigated with a focus on the effects of plating parameters and additives. Both the internal stresses of the Ni coatings and their corresponding microstructures were examined. A relationship is found that the internal stress of the Ni coating was inversely proportional to its grain size and the Ni{200}/Ni{111} peak fraction in the measured X-ray diffraction pattern. The smaller grain size, accompanied with higher Ni{111} intensity, resulted in the higher internal stress of the coating, and vice versa. A proposed theoretical model, which took both the grain size and preferred crystalline orientation into account, correlated closely with experimental results in the internal stress. As a result, the presence of surfactant in the Sc-CO2 electrolyte increased the internal stress of Ni coating. However, a reduction of internal stress is made possible by varying four factors: the raising of current density, the increasing of plating temperature, the lowering of plating pressure, and the addition of saccharin into electrolyte. A comparison to the internal stress of Ni coatings plated by the conventional method was also discussed in this study.

Systematic nanoindentation experiments have been carried out to study the mechanical properties of a nanocrystalline Fe–51Ni coating exhibiting anelastic and creep characteristics. An analytical method based on the correspondence principle for linear viscoelasticity was developed. The holding displacement–time data obtained in indentation creep tests at a high loading rate of 20 mN/s were analyzed, and material parameters related to the elastic, anelastic, and creep characteristics were derived using a model containing one Maxwell unit and two Kelvin units. The anelastic deformation thus contains at least two relaxation processes having relaxation times of 0.37 and 6.8 s, respectively, and the creep deformation is described by a viscosity value of 4.2 × 104 GPa·s for the alloy in an as-deposited state. The anelastic and creep characteristics descend associated with increases of the elastic modulus and hardness values after the alloy was annealed at 673 K.

In this study, a novel inflatable belt-type clamp is introduced and its performance is verified. Finite element simulations are performed to compare the performance of three different aorta clamping systems. In every case, the aorta is modeled as a simple hollow cylinder made of linearly elastic material. For a traditional surgical clamp in which the jaws remain inclined to one another as they close around the aorta, the maximum normal stress within the aorta wall is found to be 806kPa. It is shown that the numerical results are in good qualitative agreement with the experimental results obtained using a pressure sensitive film. The simulation results for a modified clamp in which the jaws remain parallel during the clamping operation show that the maximum normal stress is reduced to 222kPa. However, two regions of maximum stress are induced within the aorta wall. Finally, the numerical results for a novel inflatable belt-type clamp show that the maximum normal stress is equal to approximately 221kPa. In contrast to the modified clamp, the stress is uniformly distributed around the perimeter of the aorta, and thus the risk of aortic dissection is significantly reduced.

The anodized aluminum oxide (AAO) template was used in the electrodeposition of Ni-P alloy in this study. The fabricated Ni-P wires were 70 to 80 nm in diameter and 15 to 20 μm in length. The analyses employing a field-emission scanning electron microscope, X-ray diffraction, transmission electron microscope, and X-ray photoelectron spectrometer (XPS) showed these nanowires were amorphous structure mixed with nanosized grains and had preferred orientation along its length. From the cathodic polarization measurements in 0.5M H2SO4 electrolyte, it was found that the Ni-P nanowires demonstrated a nearly double magnitude in the current at –0.75 VSCE compared with its solid film counterpart. Thus, the enhancement of the electrocatalytic activity due to the increase in the surface area of the nanowired structure was demonstrated and discussed. However, the formation of oxide film on the surface of the nanowire was discovered after cathodic polarization. The effect of the oxide film was also discussed in this article.

This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies, with the known advantage of low processing temperature (EN = 90 °C and CAE = 230 °C), to treat the austempered ductile iron (ADI) substrate. The eligibility of applying the EN and CAE–CrTiAlN duplex coatings on ADI, along with the coating properties, such as structure, roughness, and adhesion, were evaluated and analyzed. Moreover, polarization and immersion tests were performed to further understand the effects of the coatings on the corrosion resistance of ADI. The results showed that the unique microstructure of ADI did not deteriorate after EN and CAE treatments. With regard to corrosion resistance, the duplex coated specimens performed better than did the uncoated and monolithic EN or CrTiAlN coated ones in 3.5 wt.% NaCl and 10 vol.% H 2 SO 4 aqueous solutions.

The corrosion behavior of electrodeposited Ni-P coating in 5 pct (in weight) NaCl solution has been studied. The microstructure of the Ni-P electrodeposit displayed a layered structure composed of nanocrystalline grains revealed by transmission electron microscopy (TEM). With the increase in polarization potential and bath temperature, the corrosion rate as well as the weight loss was significantly increased. Under observation by a field-emission scanning electron microscope (FESEM), the pitting evolved into larger sizes with a diameter of approximately 30 μm as the temperature and potential were increased to 50 °C and 600 mVSCE, respectively. Cracks and delamination among the layered structure were found inside the deepened corrosion pit. The increase in surface P content and the trace of the formation of phosphate were also observed by using X-ray photoelectron spectroscopy (XPS) analysis.

The dynamic characteristics of the shape memory alloy (SMA) helical spring proposed to be used in the semi-active suspension platform (e.g. the optic disk drive) are considered in this study. The component mounted on the platform generates periodic oscillation due to parametric excitation, such as rotation of an eccentric mass. In this way, the induced vibration of the platform could load the suspension spring in both axial and lateral directions. Besides its tunable dynamic characteristics by phase transformation, the SMA helical spring providing both axial and lateral flexibilities is applicable in this regards. In this paper, the spring constant of the helical spring in transverse deformation was first derived by employing the first theorem of Castigliano's. The derived spring constant was then used to define the equivalent flexural stiffness of the spring. Consequently, the natural frequency of a stepped composite beam with the assembly of SMA spring and other beam-like component was derived by transfer matrix method. The calculated natural frequencies of the stepped beam were compared with the experimental measurements. It is found that the formulation well predicted the natural frequency of the SMA spring both in martensite and austenite phases, respectively. The tunable characteristics of the SMA helical spring in lateral vibration were also demonstrated.

The electrorheological (ER) fluid between two circular electrodes subjected to oscillatory squeeze flow is studied theoretically in this paper. The ER fluid is modeled as a bi-viscous fluid with Bingham-like behavior. The inertia due to the oscillatory flow of the fluid is taken into account. The solution is derived in the complex domain. The magnitude of the total reactive force on the upper electrode and its phase lag with respect to the electrode displacement are calculated numerically. The results show that the phase lag is more sensitive to the inertia effect than the magnitude of the reactive force. It is also shown that, within 10% discrepancy in the magnitude of reactive force, the quasi-static model can be used with actuating frequency lower than 400 Hz for the examples studied.

The demand for non-impact printers has grown considerably with the advent of personal computers. For entry-level mass production, two drop-on-demand techniques have dominated the market - piezoelectric impulse and thermal-bubble types. However, the high cost of the piezoelectric printhead and the thermal problems encountered by the thermal-bubble jet printhead have restrained the use of these techniques in an array-type printhead. In this study, we propose a new design of printhead with an electro-rheological (ER) fluid acting as a control medium. The ER fluid valve controls the ink ejection. As a first step toward developing this new printhead, the characteristics of an ER fluid valve which controls the deflection of the elastic diaphragm are investigated. First, the response of a prototype is tested experimentally to prove the feasibility of using this ER valve for the inkjet printhead. Then, the discretized governing equation of the ER valve is derived. Finally, the prototype of the ER valve is fabricated. The experimental measurement based on the sinusoidal response verifies both the theoretical analysis and the controllability of the response of the ER valve by the applied electric field.

For most composite structures, because of the uncertainty in some design variables, it is not possible to predict precisely the stresses during design stage. Therefore, monitoring the structural responses in service becomes crucial for structure with concerns, e.g., the composite panels on an airplane, etc. In this study, the strains at neighboring points of the interested location on surfaces of the laminate, along with the classical laminate theory and the higher-order shear deformation theory, are used to predict the interlaminar shear stresses in the cross-ply laminate. Several numerical examples using the simulated surface strains are employed to evaluate the accuracy of the proposed technique. It is found that the approach using the higher-order shear deformation theory has improved accuracy for the analysis of thick symmetric laminate over the approach using the classical laminate theory.

To meet a growing need in biological and medical applications, innovative micro-electro-mechanical system (MEMS) technologies have realized important progress on the micropump as one of the essential fluid handling devices to deliver and control precise amounts of fluid flowing along a specific direction. This research proposes a piezoelectric (PZT) valveless micropump adopting an integrated diffuser/nozzle bulge-piece design. The pump mainly consisted of a stainless-steel structured chamber with dimensions of 8 mm in diameter and 70 μm in depth to enhance its long-term reliability, low-cost production, and maximized liquid compatibility. A PZT diaphragm was also used as a driving source to propel the liquid stream under actuation. As commonly used indices to describe pump operation, the delivered volumetric flow rates and pressures were determined at bulge-piece diameters of 2, 4 and 6 mm, with a driving voltage of 160 Vpp and frequency ranging from 50 to 550 Hz. Measurements and simulations have successfully shown that this micropump is capable of operating at a greater volumetric flow rate of up to 1.2 ml min−1 with a maximum back pressure of 5.3 kPa. In addition, the time-recurring flow behavior in the chamber and its relationship to the pumping performance were examined in detail.

Nickel-phosphorus deposits with various phosphorus contents and internal stresses were electroplated from a nickel sulfamate bath without an additive by varying the duty cycle and frequency of the pulse current. A reduction in the duty cycle increased the phosphorus content and decreased the internal tensile stresses in the deposit. At a 0.1 duty cycle, a deposit with slightly compressive internal stress was produced. A deposit with a thickness of several hundred micrometers was plated at 0.1 duty cycle on a copper plate with good adhesion. Because the waveform parameters of the pulse current strongly affects the current efficiency and the microstructure of the deposit, the internal stress of the deposit as a function of the current efficiency, phosphorus content, and grain size was measured and discussed.

Anodization behaviors of AZ91 magnesium alloys in strongly alkaline solutions with and without the addition of fluorine ions have been studied with the emphasis on the effect of the Mg 17 Al 12 (β) phase. In the absence of F - ions, the potential of the cell was relatively low and sparks were absent throughout galvanostatic anodizing at a current density of 1 A/dm 2 . After 10 min of anodization, a significant preferential anodization within an a matrix resulted in a nonuniform anodic film in regions of large hemispherical pits. F - ions in strongly alkaline solutions resulted in a marked increase in the cell potential and induced sparks on the alloy. These effects associated with F - ions are likely due to the formation of Mg and Al fluorides, which effectively retards the preferential surface attacks in a strongly alkaline solution. Finally, the anodic film formed without sparking was mainly Mg hydroxide, whereas that resulting from sparking was primarily Mg oxide.

The microstructural evolution of the plasma electrolytic anodic coating on AZ31 magnesium alloy in an alkaline silicate solution system was studied. Voltage as high as 300 V was observed in the constant current density anodization and caused a characteristic coating transformation from a single thin porous layer to a multilayered microstructure during the anodization process. This transformation was greatly contributed to physical breakdown behaviors of the thin dielectric, during which, closed and open types of defects were observed. Such defect distribution and density in the barrier dielectric thin film were highly likely to affect the sparking behaviors as well as the resultant coating formed. In a 10 min run of anodization, a near-amorphous, silicate-containing, dense-to-porous overcoat was observed, under transmission electron microscope, attaching to a fluoride-rich barrier layer. In chemical analyses, fluoride contents were concentrated in the barrier layer along the magnesium substrate, while silicate contents were distributed away from the barrier layer in increasing amounts during the growth evolution.

In this study, nickel-phosphorus (Ni-P) deposits were electroplated from the nickel sulfamate bath containing phosphorous acid using a pulse current, with emphasis on the effect of current density, duty cycle, and frequency of the pulse current. Experimental results show that both the deposit phosphorus content and current efficiency were substantially enhanced by employing the pulse current, preferentially at low duty cycles. The underlying difference for the dc and pulse currents on the effect of deposit phosphorus content and current efficiency can be explained by the detailed half-reactions relevant to incorporation of phosphorus into Ni-P alloys. Less variation in surface proton, Ni 2+ and H 3 PO 3 concentration due to the diffusion recovery during the time off of a pulse current is believed to play an important role in the improvement of the plating process.

The properties of conversion coating on magnesium can be closely related to its microstructure and composition. This study investigated the evolution and microstructure of phosphate/permanganate conversion coating on AZ31 magnesium alloy. Results show that increasing the solution temperature reduced the growth rate of the coating. The temperature effect lies in the different structure associated with the coating layer contacting the substrate: a porous layer mainly composed of magnesium, aluminum hydroxides/phosphate formed in the solution at 40°C, while a compact magnesium oxide layer formed in the solution at 80°C. The formation mechanism of phosphate/permanganate coating was discussed in detail, with emphasis on the effect of the solution temperature.

The properties of nickel-phosphorus (Ni-P) electrodeposits can be best related to their phosphorus content and microstructure. This study systematically investigated the microstructural evolution and mechanical propertiesof the deposits plated from nickel sulfamate baths containing 0-40 g dm - 3 phosphorous acid (H 3 PO 3 ). Experimental results indicate that coarse nickel grains were substantially refined with the incorporation of phosphorus into the deposit. For example, as the deposit phosphorus content was increased from 0 to 14 wt %, the structure of the deposit changed in sequence from a coarse column to a mixture of column and lamella, followed by a well-defined lamella, and finally to a homogeneous amorphous matrix dispersed with nanosized grains. Accompanied with this structural evolution, the deposit exhibited a distinct change in deposit hardness and internal stress. These properties and microstructure relationships are discussed in terms of the lattice defects in the grains and proton discharge during electronlating.

Polymeric composite laminates are being increasingly employed to fabricate parts which must be designed to operate successfully in dynamic mechanical environments under various temperatures. Current computer-aided design tools are, however, generally restricted to the modeling of these materials at ambient room temperatures. In order to develop a set of experimental data for evaluating the predictive capabilities of new computer-aided design tools for predicting the elastodynamic response of engineering structural components operating under different temperature regimes, an experimental program was undertaken to study the elastodynamic response of E-glass/Epon cantilever specimens and AS-4 graphite/Epon cantilever specimens subjected to discrete ambient temperatures in the range of −10°F to 300°F at a constant relative humidity of 75 percent. Design charts demonstrating the variation of damping and the dynamic longitudinal elastic modulus were then plotted as a function of temperature for these specimens.