The conditions required for the formation of these layers is, however, poorly understood.
In a paper published in AZojomo* by T. L. Banh, Q. T. Phan and D. B. Nguyen from Thai Nguyen University of Technology, the authors examine the conditions for the formation of the deposited layers on the rake face of Physical Vapour Deposited Titanium Nitride (PVD-TiN) coated HSS cutting tools. These conditions were then correlated to tool wear.
It is evident from this study that the chemical composition of the inclusions in the steels does not play an important role in the formation of the layers. However, the existence of silicate inclusions in steel, especially their sizes and shapes, has a direct influence on layer formation. The existence of the silicate inclusions eliminates a built-up edge (BUE) on the cutting edge and may be involved with the formation of the white layer in the crater wear, leading to a reduction in tool wear.
The article is available to view at http://www.azom.com/Details.asp?ArticleID=3131
*AZojomo publishes high quality articles and papers on all aspects of materials science and related technologies. All the contributions are reviewed by a world class panel of editors who are experts in a wide spectrum of materials science. [See http://www.azom.com/Journal%20Editorial%20Board.asp]
AZojomo is based on the patented OARS (Open Access Rewards System) publishing protocol. The OARS protocol represents a unique development in the field of scientific publishing – the distribution of online scientific journal revenue between the authors, peer reviewers and site operators with no publication charges, just totally free to access high quality, peer reviewed materials science. [See http://www.azom.com/azojomo.asp and http://www.azom.com/oars.asp]