Control and monitoring system prototype for pulse plasma sintering process
Cubic boron nitride is commonly used as a cutting tools material for the sake of its high hardness and wear-resistance. Pulse Plasma Sintering was proposed to decrease the production costs. This method is very attractive for industry, because it significantly decreases the costs of production. The goal of this paper is to present the control system prototype for Pulse Plasma Sintering processes based on programmable logic controller. Only sintering process with carefully controlled parameters allows to restrict the transformation of cBN into hBN and guarantee production of high-quality cubic boron nitride samples. Thus a dedicated control system was developed to control parameters and therefore to improve the production process. This paper presents also a visualisation system which allows the operator to control, monitor and analyze the production process. Prepared application consists of manual and auto operating mode.
Sintering Diamond/Cemented Carbides by the Pulse Plasma Sintering Method
Under the conditions of thermodynamic instability, we produced dense sintered composites built of diamond particles (30 vol%) and a cemented carbide matrix. The composites were consolidated by high-current electric pulses at a temperature of about 1100°C and load of 75 MPa for 5 min. The diamond particles are strongly bound with the cemented carbide matrix, by a transition layer composed of a solid solution of carbon and tungsten in cobalt. No graphite precipitates were found in the sintered composites, as examined by microstructure observations, examinations of the phase composition, and an analysis of the Raman scattering spectra. The hardness of the diamond/cemented carbide was 23 GPa.
The effect of tungsten buffer layer on the stability of diamond with tungsten carbide–cobalt nanocomposite powder during spark plasma sintering
Abstract WC–Co nanocomposite powder produced by spray pyrolysis–continuous reduction and carbonization technology, diamond coated with tungsten (W) by vacuum vapor deposition and uncoated diamond were used in this study. This work adopted the spark plasma sintering (SPS) process to prepare diamond-enhanced ultrafine WC–Co cemented carbide composite material. The effects of W buffer on the stability of diamond with WC–Co nanocomposite powder during SPS were investigated. Results showed that the uncoated diamond was mechanically embedded in WC–Co cemented carbide matrix, while the diamond coated with tungsten was combined chemically with WC–Co cemented carbide matrix. Moreover, there was a transitional layer between the diamond and the matrix which could improve the thermal stability of the diamond, prevent carbon atom of the diamond from dissolving in Co phase and increase the bonding strength of the interface between the diamond and the matrix.