磁过滤电弧离子镀制备TiAlN涂层的结构与性能表征

采用磁过滤电弧离子镀技术在高速钢基体上沉积TiAlN涂层。研究了N_2分压对TiAlN涂层的相结构、化学成分、力学性能、沉积速率、表面粗糙度、结合强度以及摩擦磨损性能的影响。结果表明,N_2分压的变化对涂层的结构与性能影响显著。随着N_2分压的增加,TiAlN涂层呈现(111)择优取向,其硬度最高可达34 GPa。涂层的沉积速率和表面粗糙度随着N_2分压的增大而逐渐降低。此外,由于大颗粒的去除使得涂层表面质量得到提升,所制备的TiAlN涂层均具有较低的摩擦系数(0.15~0.33),并且呈现良好的抗磨损性能,其最低磨损率为8.8×10~(-7)mm~3/(N·m)。     

硬质合金基体对TiAlN/TiAlSiCrN/TiSiN多层涂层结构和机械性能的影响

采用电弧离子镀在YT15、YG6、YG10这3种WC基硬质合金基体上沉积了TiAlN/TiAlSiCrN/TiSiN多层涂层,并对所沉积涂层的截面形貌、截面成分、晶体结构、硬度及结合强度进行了检测与分析。结果表明:TiAlN/TiAlSiCrN/TiSiN多层涂层呈内、中、外的"三层"结构。WC基硬质合金基体通过涂层-基体界面处元素的扩散影响沉积在基体表面涂层的结构,YG10基体中W、Co元素向涂层的扩散明显,削弱了涂层的柱状结构,而YT15和YG6基体上所沉积涂层其Ti、Al元素向基体的扩散,对TiAlN内层柱状结构的影响并不明显。多层涂层的晶体取向均以TiN(200)和CrN(200)为主,且不同硬质合金基体上沉积的涂层其衍射峰强度不同。沉积在YG10表面的涂层获得最大硬度,为4 600.13 HV。基体与涂层硬度差影响涂层结合性能,硬度差越小,涂层结合性能越好,沉积在YG6上的涂层其结合性能最好,临界载荷为103.32 N。     

凸模表面沉积TiAlN涂层提高模具寿命的研究

介绍了在硬质合金MC30、KD20基体上沉积TiAlN涂层的方法,在MC30基体上沉积的涂层具有更高的显微硬度、更低的磨损速度。沉积纳米TiAlN涂层的精密IC引线框架模具寿命能提高4~6倍,在实际应用中取得很好的效果。     

TC11钛合金表面电弧离子镀TiAlN涂层防护性能的研究

利用电弧离子镀技术在TC11钛合金基体上沉积TiAlN涂层。采用扫描电子显微镜（SEM）、X射线衍射仪（XRD）等方法对比分析了钛合金基体和涂层氧化前后的表面形貌、物相结构。采用X射线光电子能谱仪（XPS）对TiAlN涂层性能进行了分析,研究了基体和镀膜的耐磨性。结果表明,TiAlN涂层显著改善了钛合金的粘着磨损性及高温抗氧化性,在空气中650℃静态氧化100h后,TiAlN涂层依然保持良好的状态和抗磨损性能。     

偏压梯度TiAlN涂层对TC4钛合金振动与拉伸疲劳性能的影响与机理

目的 探究偏压梯度TiAlN涂层对基体疲劳性能的影响规律和疲劳损伤机理。方法 利用磁过滤阴极真空弧技术和连续改变偏压的沉积工艺,在TC4钛合金表面沉积了偏压梯度TiAlN涂层,并采用扫描电镜、轮廓仪、纳米压痕和划痕仪表征测试了TiAlN涂层的微观结构和内应力、表面硬度、膜基结合力等基本力学性能。对TiAlN涂层试件的振动和拉伸疲劳性能分别进行了考核,通过观察试件疲劳断口形貌,探究了偏压梯度TiAlN涂层/基体的疲劳损伤机理。结果 TiAlN涂层中Al元素含量沿深度方向一直在降低,偏压工艺成功制备出梯度结构涂层。偏压梯度TiAlN涂层的内应力为压缩状态,数值为(2.66±0.23) GPa,显著低于对应恒压涂层(‒200 V)。偏压梯度TiAlN涂层试件平均振动强度和拉伸疲劳强度分别为370.90、377.90 MPa,前者相对于TC4基体提高了47.7%,后者几乎保持不变。结论 TiAlN涂层内部存在残余压应力,具有一定抗裂纹萌生能力,TC4钛合金表面制备偏压梯度TiAlN涂层后,两种受载类型下的疲劳裂纹源均位于涂层与基体界面处。振动受载时,涂层中梯度结构抑制了裂纹的扩展,疲劳强度提高;拉伸受载时,TiAlN涂层部分发生破碎,抑制裂纹萌生与促进裂纹扩展两种机制同时存在,疲劳强度几乎不变。     

TiN/TiAlN涂层Ti(C,N)基金属陶瓷刀具的切削性能

采用多弧离子镀技术在Ti(C,N)基金属陶瓷基体上沉积了TiN/TiAlN多层涂层,通过扫描电镜、涂层附着力自动划痕仪对其显微组织形貌和涂层的结合强度进行了分析,并对涂层和未涂层金属陶瓷铣刀以及硬质合金铣刀进行了切削0Cr18Ni9钢的试验.结果表明,多弧离子镀TiN/TiAlN涂层均匀,TiN/TiAlN多层涂层与金属陶瓷之间的结合强度高达57.52 N.TiN/TiAlN涂层金属陶瓷的切削性能明显优于未涂层金属陶瓷和硬质合会YW2,其平均寿命为硬质合金刀具的2倍.TiN/TiAlN涂层金属陶瓷刀具的失效形式主要是磨损和崩刃,没有涂层剥落现象,TiN/TiAlN涂层与基体的结合强度很好.未涂层金属陶瓷刀具的磨损形式主要是磨损和粘着.     

基体偏压对TiAlN涂层性能的影响

基体偏压是多弧离子镀沉积TiAlN涂层工艺中的一个重要参数,它对涂层的结构以及涂层生长速度有重要影响.通过改变沉积过程中的基体偏压,发现TiAlN涂层表面熔滴的密度和直径随基体负偏压的增加而减小,涂层的显微硬度随着基体负偏压的增加而增加,孔隙率随着基体负偏压的升高而降低.     

TiN/TiAIN涂层的断裂韧性研究

采用多弧离子镀技术在Ti(C,N)基和WC基金属陶瓷基体上沉积了TiN/TiAlN涂层,利用维氏硬度计对涂层进行压痕试验;通过测试压痕周围的裂纹长度和数目,用裂纹密度β来评价涂层的断裂韧性.结果表明,Ti(C,N)基金属陶瓷基体上TiN/TiAlN涂层的裂纹密度为4558,比WC基金属陶瓷基体上涂层的裂纹密度低.TiN/TiAlN涂层的压痕形貌中,涂层没有剥落,只有沿压痕应力角径向显微裂纹和压痕四周的侧向显微裂纹,不同基体其压痕裂纹特点也不同.Ti(C,N)基金属陶瓷基体上涂层的径向裂纹非常短,并有裂纹偏转现象,侧向裂纹很长.WC基金属陶瓷基体上涂层的径向裂纹很长,非常平直,侧向裂纹很短.     

金属陶瓷多弧离子镀TiN/TiAlN涂层的结构与性能

采用多弧离子镀技术在Ti(C,N)基金属陶瓷基体上沉积了TiN/TiAlN涂层,通过扫描电镜、能谱仪、X射线衍射仪、原子力显微镜等分析技术对其显微组织、成分、相结构、粗糙度及涂层与基体间的结合强度进行了分析.结果表明,多弧离子镀TiN/TiAlN涂层后试样的表面为金黄色,涂层光滑平整,其均方根粗糙度为20.6 nm,显微硬度达到2808 HK.TiN相和TiAlN相均存在强烈的(111)择优取向.Al的含量从涂层内部到表面逐渐增大,呈现梯度分布特征.TiN/TiAlN涂层与金属陶瓷之间的结合强度高达57.52 N.     

LD钢TiAlN涂层的制备及性能

采用电弧离子镀工艺在7Cr7Mo2V2Si模具钢(LD钢)表面沉积TiAlN涂层。通过X射线衍射仪、扫描电镜、维氏硬度计、磨损试验机和电化学工作站等手段对TiAlN涂层的综合性能进行了分析。结果表明:涂层表面平整、致密,截面无针孔等缺陷存在,其择优取向为(200)晶面。涂层基体之间有1μm左右的互扩散层,使得膜基之间的结合力牢固。涂层的耐磨性能良好,其磨损率为0.122 mg/h,涂层试样与基体相比相对耐磨性提高了1.25倍。在2300×10~(-6)硼酸溶液中,LD钢TiAlN涂层自腐蚀电流密度比基体降低了一个数量级,阻抗较基体高了1.66倍,TiAlN涂层提高了LD钢的耐硼酸腐蚀性能。剪切考核试验表明TiAlN涂层刀具的寿命比原来提高了约2倍。     

TiAlN涂层刀具研究新进展

TiAlN涂层具有硬度高、氧化温度高、热硬性好、附着力强、摩擦系数小,导热率低等优良特性。作为一种性能优异的新型涂层材料,TiAlN涂层成功的替代了TiN涂层,具有极其广阔的应用前景。对TiAlN涂层的特性、TiAlN涂层刀具的应用,TiAlN涂层刀具后处理技术以及其研究进展与发展趋势做了系统介绍。     

Electro-spark coatings for enhanced performance of twist drills

Surface engineering approaches are being increasingly employed for enhancing the effective life of twist drills with a view to reduce machining costs. The electro-spark coating (ESC) technique provides a promising means of depositing wear resistant coatings that can potentially enhance the performance of these tools. However, it is often necessary to also optimize the machining conditions for coated tools to achieve an enhanced tool life. In the present investigation, varying spindle speeds were employed at a fixed vertical feed to evaluate the performance of WC-8Co ESC coated HSS drills in comparison to bare HSS drills. The number of holes drilled before reaching a preset average flank wear (0.5 mm), or catastrophic failure of the drill, was taken as the measure of tool life. The drill flank wear, monitored at regular intervals, as well as the cutting torque and thrust measured for all holes, were considered to be the key criteria for optimizing the cutting conditions. Results indicate that the WC-8Co coated drill tool life can be increased by a factor of more than 5, depending on the machining conditions selected. Furthermore, flank wear of the drill was found to increase rapidly at the end of drill life. Cutting torque data was also found to provide a useful indicator for predicting the end of tool life.     

W6Mo5Cr4V2Al高速钢麻花钻断裂原因分析

利用化学成分分析、光学显微镜、扫描电镜以及能谱分析等手段研究了W6Mo5Cr4V2Al高速钢麻花钻的断裂原因。结果表明,麻花钻在热处理过程中发生过热、过烧,导致局部晶界熔化,基体内形成共晶莱氏体和大量网状碳化物,冷却时在表面形成较高的拉应力,当应力大于材料的断裂强度时产生沿晶裂纹,在随后的校正过程中,在外力作用下发生了断裂。     

SEM study of defects in PVD hard coatings using focused ion beam milling

Hard coatings CrN, TiAlN and multilayer CrN/TiAlN were prepared on different substrates (HSS, D2 tool steels, Al-alloy) by thermoionic arc ion plating and by sputtering. The defects incorporated into the coating were studied by four techniques: top view conventional and field-emission SEM, cross-section SEM, AFM and stylus profilometry. As a specifically useful tool to study internal structure of the defect, we applied focused ion beam milling system, which is built in a conventional scanning electron microscope. By ion beam milling we prepared cross-sections through the defects.     

A study of high-performance plane rake faced twist drills.: Part I: Geometrical analysis and experimental investigation

A study of a modified drill point design with plane rake faces for drilling high-tensile steels is presented. A geometrical analysis has shown that the modified drill point design yields positive normal rake angle on the entire lips and point relieving in the vicinity of the chisel edge. This drill geometry can be expected to reduce the cutting forces and torque, and hence reduce the possible drill breakages when drilling high-tensile steels. An experimental study of drilling an ASSAB 4340 high-tensile steel with 7–13 mm titanium nitride (TiN) coated high-speed steel (HSS) drills has shown that the modified drills can reduce the thrust force by as much as 46.9%, as compared to the conventional twist drills under the corresponding cutting conditions, while the average reduction of torque is 13.2%. Drill-life tests have also been carried out and confirmed the superiority of the modified drills over the conventional twist drills. In some cases, the conventional drills were broken inside the workpiece, while the modified drills performed very well under the same cutting conditions. To mathematically predict the drilling performance and optimise the drilling process using the plane rake faced drills, predictive models for the cutting forces, torque and power will be developed in the second part of this investigation.     

The study on the chip formation and wear behavior for drilling forged steel S48CS1V with TiAlN-coated gun drill

The solid carbide gun drill was coated with TiAlN, and a comprehensive evaluation on the wear behavior and chip formation had been performed on it for machining forged steel S48CS1V at a cutting speed of 12.66 mm/s (4400 rpm) with a continuous Minimum Quantity Lubrication (MQL). Cutting torque had been measured versus with the quantity of the machined crankshaft. The cutting torque curves revealed the three wear stages that were the initial stage, the semi-steady stage and the disastrous stage. Gun drill with TiAlN coating suffered from adhesive wear on the wear pad and chemical diffusion wear on flank face. Additionally, sliding wear and chipping were the wear forms. The high temperature and stress played the important roles in the adhesive and chemical diffusion wears. The high alternative stress produced the plastic deformation and cold welding for the atomic absorption and thus it made the grains of carbide substrate tearing-off from deforming cobalt bond, therefore adhesive wear took place.     

Magneto-abrasive machining for the mechanical preparation of high-speed steel twist drills

In this paper investigations of the influence of magneto-abrasive machining (MAM) on the micro-geometry of the tool cutting edges and the surface quality of high-speed steel (HSS) twist drills are presented. It is shown that MAM makes it possible to reproduce defined radii of the cutting edges and corner edges of the drills and improves the tool surface quality. The optimally rounded cutting corner edge of the drill makes it possible to avoid the run-in period of the drill and increases the stability of the cutting edge substantially. This results in an improved wear behaviour and higher tool life of the drill.     

The Study of Deposition Parameters, Properties for PVD Ti_xN and Cr_xN Coatings Using a Closed Field Unbalanced Magnetron Sputter Ion Plating System

DIFFERENT PVD TECHNIQUES have been used todevelop a wide range of hard wear resistant coatings onsteel substrates since the early1980's.These coatingshave proved successful in improving the performanceof cutting tools[1].Closed field unbalancedmagnetron sputter ion plating(CFUBMSIP)is anexceptionally versatile technique,developed by TeerCoatings Ltd,for the deposition of high-quality;well-adhered thin films[2].Compared to other ordinarymagnetron sputter techniques,the CFUBMSIPt…     

Metallurgical Characteristics of TiAlN/AlCrN Coating Synthesized by the PVD Process on a Cutting Insert

TiAlN/AlCrN coating was deposited on a tungsten carbide insert, using the plasma-enhanced physical vapor deposition (PEPVD) process. The microstructure of the coating was examined and it was found that the TiAlN/AlCrN coating was uniform, highly dense, and less porous. The different phases formed in the coating were analyzed using the x-ray diffraction. The hardness and scratch resistance were measured using the nanoindentation tester and scratch tester, respectively. TiAlN/AlCrN exhibited higher hardness, higher Young’s modulus, and superior scratch resistance when compared to the conventional coatings, such as TiAlN, AlCrN, and TiN. The surface morphology of the coating was characterized using the atomic force microscope (AFM). The surface roughness was found to be lesser in the TiAlN/AlCrN coating. The TiAlN/AlCrN coating has proved to have better corrosion resistance, compared to the uncoated carbide substrate.     

New type drill with three major cutting edges

Drilling performance of a new type twist is described. The new type drill has three major cutting edges, three chisel edges and three flutes. This drill is an efficient means of making a hole with high accuracy and no reaming. Recently, some research on drill materials including surface coating, drill point geometry, cutting forces and tool life have been carried out in order to increase the cutting performance of drills. All the drills used in these experiments were ordinary drills with two major cutting edges. The authors calculated the point geometry of the new type drill, and also examined the cutting characteristics of the drill with respect to cutting forces, hole accuracy and tool vibration. The experimental results showed that the whirling vibration which frequently occurs in an ordinary drill with two major cutting edges disappears when the new type drill is used, and thereby rifling marks do not results on the hole surface. Consequently, a hole with high roundness and straightness is obtained.