HARD COATED LAYER FOR CUTTING TOOLS

• Main Authors: LEE, SUNG GU, AHN, SUN YONG, AHN, JIN WOO, LEE, DONG YOUL, KIM, KYUNG IL, CHO, SUNG HUN, YEOM, JIN HEE
• Format: Patent
• Language: English; Korean
• Published: 20.07.2015
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

The present invention relates to a hard coating for cutting tools which is formed by laminating an MT-TiCN layer, a combining layer and an alumina (Al_2O_3) layer on a base metal in sequence, which can extend service life and reduce peeling-off of cutting tools since the hard coating is able to improve mechanical properties of an MT-TiCN layer by controlling fine tissue of the MT-TiCN layer and at the same time enhance the extent of adjoining with the alumina (Al_2O_3) layer located in an upper part of the MT-TiCN layer. According to an embodiment of the present invention, the hard coating is formed on a base metal made of a cemented carbide alloy or a cermet, is configured in a multi-layered structure including a TiC_xN_y(x+y=1,x>0,y>0) layer with a thickness of 1 to 20μm wherein the TiC_xN_y(x+y=1,x>0,y>0) layer occupies more than 70% of the length of Σ3 type grain boundary measured by EBSD from the sum of the lengths of Σ3, Σ5, Σ7, Σ9, Σ11, Σ15 and Σ23 type grain boundaries. 본 발명은 모재 상에 MT-TiCN층, 결합층, 알루미나(AlO)층의 순으로 적층 형성한 경질 피막으로, MT-TiCN층의 미세조직을 제어하여 MT-TiCN층의 기계적 특성을 향상시킴과 동시에 MT-TiCN층의 상부에 위치한 알루미나(AlO)층과의 밀착도를 향상시킬 수 있어, 절삭공구의 표면에 형성하였을 때, 절삭공구의 수명과 인선부의 박리를 감소시킬 수 있는 경질 피막에 관한 것이다. 본 발명에 따른 경질 피막은, 초경합금 또는 써멧(cermet)으로 이루어진 모재 상에 형성되고, 두께 1~20㎛의 TiCN(x+y=1,x＞0,y＞0)층을 포함하는 다층 구조로 이루어지고, 상기 TiCN(x+y=1,x＞0,y＞0)층은 EBSD로 측정한 Σ3 타입의 결정립계의 길이가 Σ3, Σ5, Σ7, Σ9, Σ11, Σ15 및 Σ23 타입 결정립계 길이의 합에서 70% 이상을 차지한다.