Fabrication Of WC Research Articles

Designing and Fabrication of WC p /Cu Metal-Matrix Composite by Pressureless Infiltration Technique

The WC p particulate reinforced Cu matrix composite has been designed and fabricated via spontaneous infiltration technique for the course experiment of Metal Matrix Composite. The influence of main processing parameters, including infiltration method as well as temperature on the microstructures, phase compositions and the hardness is investigated. The results show that both the fraction of WC and the hardness show a gradual decline with the increasing of infiltration temperature.

Fabrication of cemented tungsten carbide components by micro-powder injection moulding

Micro-powder injection moulding (micro-PIM) is an advanced net-shaping process for the fabrication of metal and ceramic complex micro-components. Cemented tungsten carbide (WC–Co) hardmetal is known for its high hardness and wear resistance in various applications. Micro-PIM is a new alternative manufacturing technique for hardmetal micro-parts. In this work, the fabrication of WC–Co components via a micro-PIM process was studied. A fine WC–10Co–0.8VC (wt.%) powder was mixed with a binder system consisting of paraffin wax, low density polyethylene and stearic acid. A micro-component was injected at low pressure using a semi-automatic injection moulding machine. The injection temperature was determined from the rheological investigation of the feedstock. The binder extraction was carried out in solvent and thermal debinding methods under an argon atmosphere. Thermal gravimetric analysis was used to confirm the removal of the soluble binder from the green part. The sintering process has been performed within a temperature range of 1330–1450°C under vacuum. After sintering, a density of 94.5% theoretical density was obtained, which is a reasonable value. The micro-components showed length shrinkage between 16 and 22% and good surface quality and hardness values when compared with conventional powder metallurgy. This research shows that micro-PIM is able to produce small WC–Co components with properties comparable to conventional powder metallurgy.

Fabrication of WC and WC(Co) Codeposited Nickel Composite Coating by Electroplating Method for the Replacement of Chromium Coating

The codeposition of fine WC and Co coated WC particles from nickel Watt’s bath has been investigated. Electroplating of Ni/WC and Ni/WC(Co) composites coating were carried out at different current density with variation of particle size. The effect of hydrodynamic conditions of the codeposition of Ni/WC bath has been investigated. The Guglielmi adsorption mechanism is applied to the electroplating of the fine WC and WC(Co) in Ni matrix. The adsorption rate of determination step is controlled by the transferal process of loose adsorption to strong adsorption. The embedded WC concentration can be increased both by increasing electrical current density and additional WC concentration in the bath.

Fabrication of WC–Co cermets by laser engineered net shaping

The Laser Engineered Net Shaping (LENS ®) technology is an extension of rapid prototyping technologies into the direct fabrication of metal parts. Bulk dense tungsten carbide–cobalt (WC–Co) cermets were produced without any molds using the LENS ® technology, starting from granules consisting of nanostructured WC crystallites in a Co matrix. Thermal behavior of the LENS ® process, shape change and coarsening of WC crystallites were investigated in this work to study the mechanisms of microstructural evolution of the cermets. Microstructures with alternating layers were observed, which is relevant to the thermal behavior of the LENS ® process. Variations in hardness result from the change in cooling rate along the specimen height.

A streamlined life cycle assessment on the fabrication of WC–Co cermets

Tungsten carbide–cobalt (WC–Co) cermets have been widely used because of their high hardness and excellent wear-resistant properties. In this study, the environmental burdens related to WC–Co component fabrication were evaluated to compare the Laser Engineered Net Shaping (LENS ®) process and the conventional powder metallurgy (P/M) process. Sensitivity analysis revealed that choice of weighting scheme does not significantly affect the final result; the LENS ® process is more preferable if powder recycling is applied, part size is small, or part shape is complex; and the P/M process provides more benefits to produce large parts of simple shape.

Fabrication of WC–Co coatings by cold spray deposition

Processing of cermet such as WC–Co is not easy by cold (gas dynamic) spraying although cold spray process can eliminate the degradation of the phase as compared to conventional high velocity oxy-fuel (HVOF) spraying process. In this study, WC–12∼17%Co powders with nano- and microstructures were deposited by cold spray process using nitrogen and helium gases. Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out by SEM and X-ray diffraction (XRD). The results show that there is no detrimental phase transformation and/or decarburization of WC by cold spray deposition as expected. It is also observed that nano-sized WC in the feedstock powder is maintained in the cold sprayed coatings. It seems that nano-sized WC is advantageous over micro-sized WC for cold spray deposition because higher particle velocity can be obtained with the same gas velocity. It is demonstrated that it is possible to fabricate the nano-structured WC–Co coating with low porosity and very high hardness (∼2050 HV) by cold spray deposition with reasonable powder preheating.