Hardness Of Nickel Research Articles

Analysis of the Effect of Time on Tensile Strength and Hardness of Electroplating Method Using Nickel on Aluminum 7075

The purpose of this research of aluminum electroplating with nickel is to improve the value of its tensile strength and hardness. This test was conducted to determine the effect of time towards the tensile strength and hardness of nickel on aluminum 7075 electroplating and the time required to achieve optimum conditions. The materials used in this study are aluminum 7075 and nickel plating. The finishing treatment process used was electroplating method. Fixed variables utilized in this study comprised the voltage (25 V), gap between electrodes (15 cm), amount of water (2400 ml), salt (four spoons), vinegar (1600 ml), aluminum, and nickel for plating. The variations used in immersion time were 30, 40, and 60 minutes for further tensile test and hardness test. The result of this research shows that the highest tensile strength value obtained was 546,155 MPa with 60 minutes coating time. While the value of hardness from time to time varied with the highest rate in of 30-minute coating time was 188.266 kgf/mm. According to the test results, it can be inferred that the longer coating time it takes, the higher the tensile strength rate the material obtains.

Composite coatings of nickel-vanadium-phosphorus-nitride boron

The effect on the micro hardness of nickel - vanadium coatings from the concentration of sodium hypophosphite in the range 10-30 g / l, the concentration of boron nitride from 0 to 50 g / l, and from the temperature in the range of 50 - 90 ° C was studied. The influence of these factors on the rate of coating, the appearance of the coating and the thickness of the coatings was researched. The effect of heat treatment regimes on the micro hardness of coatings is studied. Regressions equations are obtained that allow calculating the micro hardness of coatings when the composition, the temperature of the electrolyte and the heat treatment temperature change. The wear resistance of the obtained composite coating is determined. The composite coating of nickel-vanadium-phosphorus-boron nitride can be recommended for increasing the resistance of deforming tools operating at temperatures up to 600°C.

Effect of Mo addition on the microstructure and hardness of ultrafine-grained Ni alloys processed by a combination of cryorolling and high-pressure torsion

An investigation was conducted to examine the effect of molybdenum (Mo) content on the grain size, lattice defect structure and hardness of nickel (Ni) processed by severe plastic deformation (SPD). The SPD processing was applied to Ni samples with low (~0.3at%) and high (~5at%) Mo concentrations by a consecutive application of cryorolling and high-pressure torsion (HPT). The grain size and the dislocation density were determined by scanning electron microscopy and X-ray line profile analysis, respectively. In addition, the hardness values in the centers, half-radius and peripheries of the HPT-processed disks were determined after ½, 5 and 20 turns. The results show the higher Mo content yields a dislocation density about two times larger and a grain size about 30% smaller. The smallest value of the grain size was ~125nm and the highest measured dislocation density was ~60×1014m−2 for Ni-5% Mo. For the higher Mo concentration, the dislocation arrangement parameter was larger indicating a less clustered dislocation structure due to the hindering effect of Mo on the rearrangement of dislocations into low energy configurations. The results show there is a good correlation between the dislocation density and the yield strength using the Taylor equation. The α parameter in this equation is slightly lower for the higher Mo concentration in accordance with the less clustered dislocation structure.

Interfacial microstructure and hardness of nickel (Ni) nanoparticle-doped tin–silver–copper (Sn–Ag–Cu) solders on immersion silver (Ag)-plated copper (Cu) substrates

Sn–Ag–Cu composite solder has been prepared by adding Ni nanoparticles. Interfacial reactions, the morphology of the intermetallic compounds (IMC) that were formed, the hardness between the solder joints and the plain Cu/immersion Ag-plated Cu pads depending on the number of the reflow cycles and the aging time have all been investigated. A scallop-shaped Cu6Sn5 IMC layer that adhered to the substrate surface was formed at the interfaces of the plain Sn–Ag–Cu solder joints during the early reflow cycles. A very thin Cu3Sn IMC layer was found between the Cu6Sn5 IMC layer and the substrates after a lengthy reflow cycle and solid-state aging process. However, after adding Ni nanoparticles, a scallop-shaped (Cu, Ni)–Sn IMC layer was clearly observed at both of the substrate surfaces, without any Cu3Sn IMC layer formation. Needle-shaped Ag3Sn and sphere-shaped Cu6Sn5 IMC particles were clearly observed in the β-Sn matrix in the solder-ball region of the plain Sn–Ag–Cu solder joints. Additional fine (Cu, Ni)-Sn IMC particles were found to be homogeneously distributed in the β-Sn matrix of the solder joints containing the Ni nanoparticles. The Sn–Ag–Cu–0.5Ni composite solder joints consistently displayed higher hardness values than the plain Sn–Ag–Cu solder joints for any specific number of reflow cycles–on both substrates–due to their well-controlled, fine network-type microstructures and the homogeneous distribution of fine (Cu, Ni)–Sn IMC particles, which acted as second-phase strengthening mechanisms. The hardness values of Sn–Ag–Cu and Sn–Ag–Cu–0.5Ni on the Cu substrates after one reflow cycle were about 15.1 and 16.6 Hv, respectively–and about 12.2 and 14.4 Hv after sixteen reflow cycles, respectively. However, the hardness values of the plain Sn–Ag–Cu solder joint and solder joint containing 0.5 wt% Ni nanoparticles after one reflow cycle on the immersion Ag plated Cu substrates were about 17.7 and 18.7 Hv, respectively, and about 13.2 and 15.3 Hv after sixteen reflow cycles, respectively.

Preparation of the copper-phosphoric coatings and study of their microhardness

The paper represents results of obtaining the copper-phosphorus coatings on the surface of various. Technology of applying conductive copper phosphide films on metal and dielectric materials is shown. Surface preparation of metal products was in mechanical treatment, degreasing and etching with a view to expose the structure of the metal and dielectric surface is subjected to a degreasing and etching to provide the necessary roughness. The results showed that the hardness of the copper-phosphorus catings is higher than the hardness of nickel and chromium plating and chemical nickel hardness. The copper-phosphorus coatings produced by low-temperature gas-phase reduction of surface copper sulfate films consist of copper phosphide Cu3P, which imparts increased hardness of coating.

Dicing Development for low-k Copper Wafers using Nickel-Palladium-Gold Bond Pads for Automotive Application

New automotive requirements expect plastic packages to survive higher operating temperatures with extended thermal duration. Mission profiles for under-the-hood and transmission application historically specified minimal duration at maximum junction temperature, such as 50 total hours at 150C, while keeping most of the total operating duration at lower temperatures. Further module integration and more stringent environmental requirements push modules and thus plastic packages closer to the heat source. As such, new mission profiles include more than 3500 total hours at 150°C. To satisfy new automotive requirements, plastic packages must meet AEC Grade 0 or higher. One key limitation of the conventional plastic package is the use of gold bond wire on aluminum bond pad. Au-Al intermetallic degradation due to intermetallic transformation in high temperature storage condition remains the main reliability concern. More reliable intermetallic systems have been proposed that change the wire material and/or the bond pad metallization. An alternative wire material to gold, copper, has many benefits including low cost, high electrical and thermal conductivities and excellent reliability with aluminum pad metallization. Pad re-metallization using nickel/palladium, nickel/gold or nickel/palladium/gold over aluminum bond pad or copper bond pad offers a noble and reliable metal interconnect. This study focused on the development of dicing process for low-K-copper wafers having aluminum pad re-metallized with electroless nickel / electroless palladium / immersion gold Over Pad Metallization (OPM). Development wafers were pizza mask wafers on which multiple die designs and scribe grid production control (SGPC) modules were designed. SGPC modules are designed with aluminum probe pads that are used to monitor wafer-level process control. All aluminum features on the wafer were plated with nickel/palladium/gold OPM. With the hardness of nickel and palladium being more than 10 to 15 times the hardness of aluminum, OPM-plated SGPC's were much more difficult to dice than conventional SGPC's with aluminum pads. Cracking on silicon sidewall with crack propagating towards the die was found to cause back-end-of-line (BEOL) delamination and device failure. Extensive mechanical dicing studies were conducted to modulate the failures and resolve the dicing challenge. Specifically, dicing was observed to be not centered on SPGC pads on the pizza mask. Off-centered dicing produced drastic change in Ni loading at the center of the blade and on the edges of the blade. Packages underwent extensive reliability stress conditions. The associated process improvements described in this paper supported a successful integration of a 55nm die technology in Low Profile Quad Flat Package with Exposed Pad (LQFP-EP) meeting and exceeding AEC grade 0 requirements.

Evolution of the structure and hardness of nickel upon cold and low-temperature deformation under pressure

The effect of the deformation temperature ensuring different mobility of dislocations on the change of stages of the structural state of single-crystal nickel has been studied. It has been shown that the deformation temperature affects the type of arising boundaries and the degree of deformation that corresponds to the transition of the material to a new structural state. The formation of microtwins and deformation bands in the structure at the liquid-nitrogen temperature not only retards the formation of a homogeneous submicrocrystalline structure but also leads to a lesser strain hardening.

Effects of Carbon Fiber Orientation and Graphitization on Solid State Bonding of C/C Composite to Nickel

C/C composites were bonded to nickel in a vacuum, using an RF-induction furnace, with joining temperature, keeping time and joining compressive stress as variables. C/C composites with different carbon fiber orientations and heat treatment temperatures were used. The bending strength of the C/C composite/nickel joints was investigated. The fracture surface of the joints was observed using a scanning electron microscope. X-ray diffraction was performed on the joining surface of C/C composites. Changes in the microstructure and hardness of nickel near the joining interface were investigated. On the basis of the results of these experiments, the influences of carbon fiber orientation and graphitization on the solid-state bonding of C/C composite to nickel were examined. A large difference in thermal expansion coefficients between the longitudinal section of carbon fiber and nickel results in delamination at the interface. In the bending test, when the longitudinal section of carbon fiber is parallel to the joining surface, slip due to crystallographic anisotropy occurs. Therefore, good bonding between the longitudinal section of the carbon fiber and nickel is not achieved. On the other hand, good bonding to nickel along the cross section perpendicular to the carbon fiber axis becomes feasible. Therefore, in plain woven carbon fiber-reinforced carbon composite/nickel joints, the bending strength is low, while in unidirectional carbon fiber-reinforced carbon composite/nickel joints, the bending strength is equivalent to that of C/C composite. The degree of graphitization affects joinability. Strong bonding of C/C composite to nickel is accomplished with the progress of graphitization. The bending strength of the joint is equivalent to that of C/C composite. The bending strength of C/C composite/nickel joints is affected by the joining temperature, keeping time and joining compressive stress, because these factors are related to full contact of joining surfaces and diffusion of carbon atoms from C/C composite into nickel.

C/Cコンポジットとニッケルの固相接合に及ぼす炭素繊維の配向および黒鉛化度の影響

C/C composites were bonded to nickel in vacuum, using an RF-induction furnace, with joining temperature, keeping time and joining compressive stress as variables. C/C composites with different carbon fiber orientations and heat treatment temperatures were used. The bending strength of the C/C composite/nickel joints was investigated. The fracture surface of the joints was observed using a scanning electron microscope. X-ray diffraction was performed on the joining surface of C/C composites. Changes in the microstructure and hardness of nickel near the joining interface were investigated. On the basis of the results of these experiments, the influences of carbon fiber orientation and graphitization on the solid-state bonding of C/C composite to nickel were examined.A large difference in thermal expansion coefficients between the longitudinal section of carbon fiber and nickel results in delamination at the interface. In the bending test, when the longitudinal section of carbon fiber is parallel to the joining surface, slip due to crystallographic anisotropy occurs. Therefore, good bonding between the longitudinal section of the carbon fiber and nickel is not achieved. On the other hand, good bonding to nickel along the cross section perpendicular to the carbon fiber axis becomes feasible. Therefore, in plain woven carbon fiber-reinforced carbon composite/nickel joints, the bending strength is low, while in unidirectional carbon fiber-reinforced carbon composite/nickel joints, the bending strength is equivalent to that of C/C composite.The degree of graphitization affects the joining quality. Strong bonding of C/C composite to nickel is accomplished with the progress of graphitization. The bending strength of the joint is equivalent to that of C/C composite.The bending strength of C/C composite/Ni joints is affected by the joining temperature, keeping time and joining compressive stress, because these factors are related to full contact of joining surfaces and diffusion of carbon atoms from C/C composite into nickel.

Effect of Joining Compressive Stress on Solid State Bonding of Graphite to Nickel

Graphite was bonded to nickel in a vacuum using an RF-induction furnace with temperature, keeping time and joining compressive stress as variables. The bending strength of graphite/nickel joints, the changes of microstructure and hardness of nickel near the interface were investigated. Thermal stress induced in the joints was estimated by means of finite element analysis. On the basis of these results, the influences of joining compressive stress on bonding were examined. Joining compressive stress and joining temperature are important factors for close contact and strong bonding between the joining surfaces of graphite and nickel. At a high joining temperature, nickel is plastically deformed even under low joining compressive stress so that full contact and strong bonding are accomplished. At a low joining temperature, strong bonding was not achieved when joining compressive stress is low, because plastic deformation of nickel is restrained. The plastic deformation of nickel plays an important role in enabling good contact and strong bonding. The strength of the joints increased with joining compressive stress. The plastic deformation of nickel near the joining interface increases with the joining compressive stress so that graphite is elastically deformed during annealing. Therefore, compressive stress is retained on the graphite surface near the joining interface. Thermal tensile stress induced on the graphite surface after cooling is relaxed by this compressive stress.

Solid State Bonding of Graphite to Nickel

Graphite was bonded to nickel under joining compressive stress of 3 to 33 MPa in a vacuum at temperatures within the range of 973 to 1273 K using an RF-induction furnace. The influence of joining conditions on the bending strength of the graphite/nickel joint, and changes in the microstructure and hardness of nickel near the joining interface, were investigated. Thermal stress induced in the joint was estimated using the finite element method. On the basis of these results, the influence of thermal stress on the bending strength of the joint was examined Completion of the graphite/nickel joint depends on both joining compressive stress and joining temperature. At high joining temperature, good solid-state bonding under relatively low joining compressive stress becomes feasible. Axisymmetric thermoelastic finite element analysis suggests that the maximum tensile thermal stress is induced at a distance of 0.64 mm from the joining interface on the surface of graphite anal is increased with increasing joining temperature. The position of fracture in a bending test corresponds approximately to that of the maximum tensile thermal stress. Part of the thermal stress in practical joints is relaxed and less than that calculated using the finite element method. The bending strength of the joint increases with decreasing residual tensile stress on the surface of graphite. Relaxation of the maximum tensile thermal stress depends on the amount of carbon which diffuse into nickel. This may be related to changes in plasticity of both nickel and graphite, that is, changes in the amount of carbon that dissolves in nickel to supersaturation and the point defects introduced in graphite.

Electron ionization mass spectrometry of aryl- and fluoroalkyl-substituted nickel(II) β-diketonates and monothio-β-diketonates

Electron ionization positive-ion mass spectra are reported for 18 substituted nickel(II) β-diketonates and monothio-β-diketonates, NiII(RCXCHCOR′)2, where X = O or S; R = phenyl, 2-thienyl, 5-methyl-2-thienyl, or 2-naphthyl; and R′ = difluoromethyl, trifluoromethyl, pentafluoroethyl, or n-heptafluoropropyl. Each mass spectrum contains a prominent molecular ion, [NiL2]+, which, for β-diketonates, fragments mainly by elimination of the odd-electron R′• species; the resulting ion decomposes by losses of one or more even-electron neutral species to yield ions containing nickel(II). In contrast, the major fragmentation of the molecular ion of monothio-β-diketonates is loss of NiIL to yield an abundant L+ ion. Furthermore, while most ions contain nickel(II), some prominent ions contain nickel(I); among these are [NiISC(R) = CH]+ and [NiI(HCCR)]+. Interesting ions are formed by hydrogen transfer processes. The [NiHL]+ ion is favored in the spectra of β-diketonates having a phenyl substituent, consistent with hydrogen transfer to the metal from the aryl group. On the other hand, the [Ni(L–H)]+ ion, favored for the monothio-β-diketonates, could be formed by hydrogen transfer from the central position of the chelate ring or from an aryl substituent. Alternative mechanisms of formation are discussed. Some minor ions are formed by fluorine transfer to nickel. The trends in their abundances are influenced by the hardness of nickel as an acid in its different oxidation states, under the influence of the ligand donor atoms, and by the hardness of the carbon atoms of the perfluoroalkyl substituents.

Ａｌ‐４％Ｃｕ‐１．５％Ｍｇ合金の耐熱性に及ぼすニッケル添加の影響

Softening characteristics and corresponding microstructural changes due to annealing were studied on heattreated Al-4%Cu-1.5%Mg alloys containing Ni up to 4%. Age-hardenability was markedly lowered with increasing nickel content. Neither after annealing nor at elevated temperatures, hardness of nickel contained alloys seemed to be superior to that of nickel free alloy. These results were attributed to the facts that insoluble compounds containing Cu, Ni and Al were formed in nickel contained alloys, and that coarsening of precipitates (S', S) was never checked by nickel addition. It was suggested that nickel addition was not effective on heat resistance of Al-Cu-Mg alloy.

Effect of shock-stress duration on the residual structure and hardness of nickel, chromel and inconel

Sheet samples of pure nickel, chromel-A (80% Ni, 20% Cr) and inconel 600 (76% Ni, 16% Cr, 7% Fe) were simultaneously shock loaded in sandwich assemblies at a pressure of 250 kbar for shock-pulse durations of 0.5, 1.0 and 6.0 μsec utilizing a flying plate. The residual microhardness of all samples was observed to be increased by shock pulses in the range of approximately 0.5 – 2 μsec, to saturate at 2 μsec and to decrease in hardness in the range of 2 – 6 μsec. Examination of the residual substructures by transmission electron microscopy revealed a slight decrease in dislocation cell size in the range of 0.5 – 6 μsec, with a change in average dislocation density corresponding to the variations in residual hardness. Dislocation densities in the chromel-A and inconel 600 also corresponded to the residual hardness trend, and the deformation twin width was observed to vary from approximately 50 Å at 0.5 μsec to 150 Å at 6 μsec. The volume density of deformation twins did not vary appreciably in the same pulse-duration range. The results demonstrate an apparent interdependence of shock-stress amplitude and shock-stress duration in the effect of shock deformation on the residual structure and hardness of metals and alloys; that is, hardness can be increased by increasing the shock pressure at constant pulse duration or by increasing the pulse duration at a constant shock pressure.