Аңдатпа
The study examines the effect of ZrO2 micropowder additive (at 3 and 6 wt%) on the mechanical performance and wear behavior of 25Cdiamond–(70.5WC–4.5Co) composites fabricated by spark plasma sintering (SPS), as well as the performance of impregnated drill bits based on these composites during exploration drilling in Kazakhstan. It was found that introducing 3 wt% ZrO2 into the 25Cdiamond–(70.5WC–4.5Co) composite reduces the wear rate by weight WR from 9.124±0.544 ⋅ 10–5 to 4.116±0.382 ⋅ 10–5 g/m, by volume WV from 9.237±0.645 ⋅ 10–12 to 4.220±0.424 ⋅ 10–12 m³/s, and the specific wear rate WS from 7.142±0.512 ⋅ 10–13 to 4.022±0.254 ⋅ 10–13 m³/(N ⋅ m). The twofold increase in wear resistance observed in the 25Cdiamond–(67.68WC–4.32Co)–3ZrO2 composite compared to the base 25Cdiamond–(70.5WC–4.5Co) is attributed to grain refinement of WC, improved fracture toughness, and the transformation of the metastable tetragonal phase t-ZrO2 into the thermodynamically stable monoclinic m-ZrO2 phase. Even lower wear values were recorded for the 25Cdiamond–(64.86WC–4.14Co)–6ZrO2 composite: WR = 2.107±0.204 ⋅ 10–5 g/m, WV = 2.102±0.162 ⋅ 10–12 m³/s, and WS = 1.724±0.118 ⋅ 10–13 m³/(N ⋅ m), which is approximately 4.3 times lower than those of the base sample. The superior wear resistance of the 6% ZrO2 composite is linked to a higher content of the monoclinic m-ZrO2 phase, resulting from a more complete transformation of t-ZrO2. Field tests showed that the drilling footage achieved by the impregnated core bit based on the 25Cdiamond–(64.86WC–4.14Co)–6ZrO2 composite was four times greater than that of the standard core bit based on the 25Cdiamond–(70.5WC–4.5Co) mixture during exploration drilling by «KazakhmysBarlau» LLP. Keywords: diamond core drill bit; composite; tungsten carbide; cobalt; zirconium dioxide; wear resistance; spark plasma sintering.