Abstract
Enhanced cubic boron nitride (CBN) blade tip systems are being increasingly used for improving engine efficiency. As the matrix and CBN particles can rapidly degrade under frictional heat generated during abradable seal cutting, the metallic undercoat provides oxidation protection to the underlying base metal during engine life. A metallic undercoat CoNiCrAlY will be replaced by a hafnium- and silicon-bearing, or a rhenium-bearing NiCoCrAlY system. The newer coatings have better oxidation and creep resistance, and help minimize base alloy cracking and damage after CBN particles wear off. A progressive series of CBN particles were tested, including monocrystalline CBN to provide better angular cutting, and other enhanced CBN particles for improved thermal performance. Due to the inherent nature of the CBN electroplating process, the aluminum content of the matrix is low. MCrA1Y coatings depend on an adherent alumina scale to provide good oxidation protection.
Original language | English |
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Pages | 54-56 |
Number of pages | 3 |
Volume | 170 |
No | 5 |
Specialist publication | Advanced Materials and Processes |
State | Published - May 2012 |