Carborundum printmaking is a collagraph printmaking technique in which the image is created by adding light passages to a dark field, normally, cardboard or wood plates are coated in a layer of Silicon carbide (SiC), also known as carborundum, is a compound of silicon and carbon, synthetic silicon carbide powder has been mass-produced since which year?
Silicon carbide:  Synthetic silicon carbide powder has been mass-produced since 1893 for use as an abrasive.
i don't know