ABRASIVE SURFACED ARTICLE FOR HIGH TEMPERATURE SERVICE

摘要

A very thin abrasive material on a substrate is comprised of ceramic particulates contained within a metal matrix. The particulates extend fully through the matrix from the substrate surface to the machined free surface of the abrasive. In a representative 0.38 mm abrasive the particulates are sized normally at 0.42-0.50 mm and have an aspect ratio of less than 1.9 to 1. This enables a high density of particulates, in the range 33-62 per cm2, while at the same time ensuring good bonding in that most of the particulates are fully surrounded by matrix. When the abrasive is applied to the tip of a superalloy gas turbine engine blade, about 10-50% of the matrix metal is removed after machining. This allows the machined ceramic particulates to project into space and to thus better interact with ceramic abradable seals. In the preferred practice of the invention the particulates are alumina coated silicon carbide contained in a nickel superalloy matrix.