Cutting Instrument and Coating

Abstract

A new and improved cutting instrument is provided having an enhanced coating. The coating includes titanium, chromium, nitrogen and carbon elements and provides increased wear resistance. The coating can be applied to a variety of metal and non-metallic substrates, which include scissors and knife blades.

1 . A cutting instrument comprising:
 a cutting blade comprising steel; and   a coating disposed directly on the cutting blade, the coating comprising at least a first layer comprising an amorphous material including carbon, titanium, chromium, and nitrogen, wherein at least some of the chromium is in the form of chromium carbonitride and titanium chromium carbonitride and at least some of the titanium is in the form of titanium carbonitride, and further wherein the coating comprises the elements chromium and titanium in a weight ratio in the range of 3:1 to 1:3.   
     
     
         2 . The cutting instrument of  claim 1 , wherein the coating comprises the elements chromium and titanium in a weight ratio of 1:1 to 3:1. 
     
     
         3 . The cutting instrument of  claim 1 , wherein the coating comprises the elements chromium and titanium in a weight ratio of about 3:1. 
     
     
         4 . The cutting instrument of  claim 1 , wherein the coating comprises titanium nitride and chromium nitride. 
     
     
         5 . The cutting instrument of  claim 1 , wherein the coating has a thickness in the range of about 0.1 microns to about 0.6 microns. 
     
     
         6 . The cutting instrument of  claim 2 , wherein the coating has a nanoindentation hardness, as measured on a polished silicon wafer, of at least about 20 GPa. 
     
     
         7 . The cutting instrument of  claim 2 , wherein the coating has a nanoindentation hardness, as measured on a polished silicon wafer, of at least about 32 GPa. 
     
     
         8 . The cutting instrument of  claim 1 , wherein the coating is a two layered coating comprising the first layer and a second layer, each of which includes carbon, titanium, chromium, nitrogen and a carbonitride and each of which comprises the elements chromium and titanium in a weight ratio of 3:1 to 1:3, wherein the second layer has a higher ratio of chromium to titanium than the first layer. 
     
     
         9 . The cutting instrument of  claim 1 , wherein the coating has a thickness in the range of about 0.3 microns to about 0.5 microns. 
     
     
         10 . The cutting instrument of  claim 1 , wherein the coating is a two layered coating comprising the first layer and a second layer, each of which includes carbon, titanium, chromium, nitrogen and a carbonitride and each of which comprises the elements chromium and titanium in a weight ratio of 3:1 to 1:3, wherein the second layer has a higher ratio of chromium to titanium than the first layer. 
     
     
         11 . The cutting instrument of  claim 1 , wherein the coating has a nanoindentation hardness in the range of 12 GPa to 35.2 GPa. 
     
     
         12 . The cutting instrument of  claim 1 , wherein the coating has a nanoindentation hardness in the range of 26.3 GPa to 35.2 GPa. 
     
     
         13 . The cutting instrument of  claim 1 , wherein the coating is configured to reduce friction between the complementary cutting blades during use. 
     
     
         14 . The cutting instrument of  claim 1 , wherein the instrument is selected from the group consisting of scissors, knives, letter openers, and rotary paper trimmers. 
     
     
         15 . The cutting instrument of  claim 1 , wherein the coating has at least two layers, each of which includes chromium carbonitride, titanium chromium carbonitride and titanium carbonitride. 
     
     
         16 . The cutting instrument of  claim 1 , wherein the coating consists of three layers. 
     
     
         17 . The cutting instrument of  claim 16 , wherein the three layers include the first layer, an intermediate second layer and an outer third layer, and the outer third layer comprises silicon. 
     
     
         18 . A complementary blade cutting instrument comprising:
 a first and second cutting blade comprising steel; and   a coating disposed directly on the cutting blades, the coating comprising at least a first layer that includes an amorphous material including carbon, nitrogen, titanium, and chromium, wherein at least some of the chromium is in the form of chromium carbonitride and titanium chromium carbonitride and at least some of the titanium is in the form of titanium carbonitride, the coating having a thickness in a range of 0.05 microns to about 1.0 microns, and further wherein the coating comprises the elements chromium and titanium in a weight ratio in the range of 3:1 to 1:3.   
     
     
         19 . The cutting instrument of  claim 18 , wherein the coating comprises the elements chromium and titanium in a weight ratio of 1:1 to 3:1. 
     
     
         20 . The cutting instrument of  claim 18 , wherein the coating comprises the elements chromium and titanium in a weight ratio of about 3:1. 
     
     
         21 . A method comprising:
 obtaining a cutting instrument having a cutting blade comprising steel,   placing the cutting instrument in a position suitable for coating the cutting blade;   cleaning the cutting blade; and   depositing at least a first layer of a coating comprising an amorphous material including chromium, titanium, carbon and nitrogen directly on the cutting blade,   wherein at least some of the chromium is in the form chromium carbonitride and titanium chromium carbonitride and at least some of the titanium is in the form of titanium carbonitride, and   wherein the coating comprises the elements chromium and titanium in a weight ratio in the range of 3:1 to 1:3.   
     
     
         22 . The method of  claim 21 , wherein the coating is deposited by reactive magnetron sputtering. 
     
     
         23 . A cutting instrument comprising:
 a cutting blade comprising steel; and   a reactive magnetron sputtered coating disposed directly on the cutting blade, the coating having a thickness of 0.1 to 0.5 microns and comprising at least a first layer comprising an amorphous material including titanium, chromium, and nitrogen, the titanium and chromium being present in a weight ratio in the range of 3:1 to 1:3.