WC/Ni alloy composite is used as a hardfacing material to protect truck bed, which is scratched by ores when they are dumped. For this application, select one from the following two WC-Ni alloy composites, which have their WC volume fractions equal to 60% and 40%, respectively. Rubber-wheel abrasion test (sand: SiO2 ) showed that the 60% WC-Co specimen was more resistant to wear. Air-jet solid-particle erosion test (sand: SiO2, impingement angle: 75 ) showed that the 40%WCNi alloy composite was better. Which composite will you select? Why