Gas tight seal between stationary and moving parts - esp. for tips of superalloy rotor blades in gas turbines

摘要

One metal part (1) ends in a projection fitted with a tip consisting of an inner (a)- and an outer (b) zone. Tip (a) is an alloy casting with compsn. different from metal (1) and resisting oxidn., sulphur, and thermal fatigue; tip (a) is bonded to metal (1) esp. by diffusion. The outer tip (b) has a matrix (b1) based on Cr, Co and/or Ni, which contains abrasive particles (b2) longer than the thickness of matrix (b1) so particles (b2) project out of the matrix. Particles (b2) are harder than the surface of the other part (2) forming the seal with part (1). Alloy (a) is pref. a monocrystalline casting; and matrix (b1) is pref. an alloy of Ni, Cr, and Al. Used esp. where tip (a,b) is fixed on the end of a gas turbine rotor blade to form a seal in the high temp. zone of the turbine.