The Actual Application Results for the Coating of Cutting Tools(1)
Connecting layer with Decidable Role in Tungsten Carbide’s Coating Performance
The phase α, k and γ of Al2O3 are available to be used as the coating material principally, meanwhile they are capable to catch different needs as per actual application respectively . Al2O3 material with phase α has been used in the common CVD field, here the Al2O3 with phase α has excellent heat-resistance and chemical stability .
In order to fully play the strength of Al2O3 ,the coating must has enough binding capability on the substrate of TiCN,but the strong binding performance is achieved with the connection layer ,by means of it to binding the Al2O3 coating .However ,the connection layer has another important mission that form the structure texture and responsible for the crystal changes which formation of crystal geometry .
So as to get the purified Al2O3 with phase α,it must have the crystalline structure in the same structure as base .Exactly speaking ,the connection layer has to have a structure similar to a-Al2O3.Thus ,TiO is taken as the connection material in the field of high-temperature CVD coating .However ,Walter ttakes the mixed material of TiCN and Al2O3 as the connection layer with merits such as very purified phase a Al2O3 crystal and high crystalline structure at 0.001mm
Why the connection layer takes the decidable function ?It is very hard to answer ,thermal-conductivity and hardness show the directivity associated with lattice in the crystal, especially show its max value in the so-called 0.01 priority direct .Consequently ,in the actual application such as high-speed machining steel ,the cutting tools service life is available to be increased by 30%.
