Formation of tungsten carbides during pyrolysis of WCl6 and toluene

To determine the phase composition of the carbide coatings epigrams were recorded in an RKSO-2 x-ray camera with a flat film holder in the inverse position (reflection angles greater than 450 were registered). The Debye-Scherrer method was also used (RKD camera with d=57.3 mm). The work was performed in an x-ray tube with a copper anode (continuous x-rays in the first case, filtered in the second). The coating thickness was measured microscopically and by weighing. The adhesion of the coating to the substrate was determined by an MRO5-1 machine, the microhardness was measured by a PMT-3 microdurometer. Data are obtained on the effect of the substrate temperature, the ratio Csub(C7H8)/Csub(WCl6), and the duration of the process on the rate of deposition of W carbides and their phase composition. One-phase WC coatings can be obtained at Csub(C7H8)/Csub(WCl6)=6-12. The adhesion of the coatings to the W substrate can be increased by an order of magnitude by forming a sublayer consisting of a mixture of W2C and WC