ADHESION STRENGTH OF COATING SUBSTRATE AND SURFACE MORPHOLOGY OF PRETREATMENT

Premature failure of coated tool often results from a poor adhesion of coating-substrate and shortens the lifetime of the tool. The results of increasing the adhesion strength of thin film coatings on cutting tool inserts by pretreating the inserts with sandblasting technique to obtain a desirable surface morphology of the inserts are presented. A geometric model representing the ideal surface morphology is established to enhance the nucleation density and adhesion strength of coating-substrate. Thin film coating experiment is conducted on the substrates of four different sample groups. Indentation and wear tests are performed on coated inserts to evaluate the effect of sandblasting on the adhesion strength of the coatings. A theoretical analysis is provided on the formation and growth of atom clusters in terms of the contact angle and the thermodynamic barrier of a substrate to predict thin film nucleation.

TENSILE AND ADHESIVE STRENGTHS OF FINE TiN FILM ON Ti SUBSTRATE

The cantilever bending test,particularly monitored by an acoustic emission technique, was adopted to measure the tensile and interfacial adhesive strengths of the HCD ion plated fine TiN film on pure Ti substrate.The behaviors of film damaging were found to be characterized by:an internal tensile stress which exceeded its tensile strength for TiN facing upward,and a shearing stress along film substrate interface which exceeded its adhesive strength for TiN facing downward.The measured tensile and adhcsive strengths are 603 and 242 MPa respectively.

Interfacial Bonding Strength of TiN Film Coated on Si_3N_4 Ceramic Substrate

The fraction of TiN/Si3N4 in the cross section was observed with scanning electric microscope （SEM）, and residual stresses of TiN coated on the surface of Si3N4 ceramic were measured with X-ray diffraction （XRD）.The hardness of TiN film was measured, and bonding strength of TiN film coated on Si3N4 substrate was measured by scratching method. The formed mechanism of residual stress and the failure mechanism of the bonding interface in the film were analyzed, and the adhesion mechanism of TiN film was investigated preliminarily. The results show that residual stresses of TiN film are all behaved as compressive stress, and TiN film is represented smoothly with brittle fracture, which is closely bonded with Si3N4 substrate. TiN film has high hardness and bonding strength of about 500 MPa, which could satisfy usage requests of the surface of cutting Si3N4 ceramic.

Enhanced adhesion of Cu-W thin films by ion beam assisting bombardment implanting

Cu-W thin film with high W content was deposited by dual-target DC-magnetron co-sputtering technology.Effects of the substrates surface treating technique on the adhesive strength of Cu-W thin films were studied.It is found that the technique of ion beam assisting bombardment implanting of W particles can remarkably improve the adhesive property of Cu-W thin films. Indentation and scratching test show that,the critical load is doubled over than the sample only sputter-cleaned by ion beam.The enhancing mechanism of ion beam assisting bombardment implanting of Cu-W thin films was analyzed.With the help of mid-energy Ar+ion beam,W atoms can diffuse into the Fe-substrate surface layer;Fe atoms in the substrate surface layer and W atoms interlace with one another;and microcosmic mechanical meshing and diffusing combination on atom-scale among the Fe and W atoms through the film/substrate interface can be formed.The wettability and thermal expansion properties of the W atoms diffusion zone containing plentiful W atoms are close to those of pure W or W-based Cu-W film.

The Effect of Diffusion Barrier and Bombardment on Adhesive Strength of CuCr Alloy Films

A novel co-sputtering method that combined magnetron sputtering (MS) with ion beam sputtering (IBS) was used to fabricate CuCr alloy films without breaking vacuum after depositing diffusion barrier with IBS. Different bombardment energies were used to improve the comprehensive properties of Cu alloy film. The results indicated that the effects of diffusion barriers and bombardment energy on adhesive strength could be evaluated by a rolling contact fatigue adhesion test. Diffusion barrier can enhance the adhesive strength, and the adhesion of CuCr/CrN was higher than that of CuCr/TiN. When bombarding energy was higher, the adhesive strength of CuCr/TiN films was higher due to the broader transition zone.

Adhesive strength of CVD diamond thin films quantitatively measured by means of the bulge and blister test

Large advancement has been made in understanding the nucleation and growth of chemical vapor deposition （CVD） diamond, but the adhesion of CVD diamond to substrates is poor and there is no good method for quantitative evaluation of the adhesive strength. The blister test is a potentially powerful tool for characterizing the mechanical properties of diamond films. In this test, pressure was applied on a thin membrane and the out-of-plane deflection of the membrane center was measured. The Young＇s modulus, residual stress, and adhesive strength were simultaneously determined using the load-deflection behavior of a membrane. The free-standing window sample of diamond thin films was fabricated by means of photolithography and anisotropic wet etching. The research indicates that the adhesive strength of diamond thin films is 4.28±0.37 J/m^2. This method uses a simple apparatus, and the fabrication of samples is very easy.

Experimental Research of Dynamic Response of Laser-Induced Film-Substrate System

Film-substrate’s interfacial bonding strength is closely related to film quality. An excellent interfacial bonding strength is the premise for the well use of film. The laser detecting technique of discrete scratches based on laser shockwave effect is a new method, which can measure interfacial bonding strength. With this technique, film-substrate system is of transient load of different laser energy, the relation between the dynamic response characteristics of such film-substrate system and film-substrate’s interfacial bonding strength is a core problem to be solved urgently. On this basis, this paper conducted research on the dynamic response characteristics of film-substrate system during laser loading process using detecting technique of PVDF patch sensor. Results show that under the irradiation of different laser energy, it can detect dynamic responses of theory models of different film-substrate system using PVDF patch sensor, wherein shockwave dynamic response and dynamic strain response are included. Laser energy and interfacial bonding strength are of a regular influence to the dynamic response of film-substrate system theory model.

Decohesion of graphene from a uniaxially-stretched substrate:Failure analysis of a frictional adhesive interface

Composite structures consisting of two-dimensional(2D)materials deposited on elastic substrates have a wide range of potential applications in flexible electronics.For such devices,robust 2D film/substrate interfacial adhesion is essential for their reliable performance when subjected to external thermal and mechanical loads.To better understand the strength and failure behavior of the 2D film/substrate interfaces,two types of graphene/polymer samples with distinct interfacial adhesion properties are fabricated and tested by uniaxially stretching the substrates.Depending on the interfacial adhesion,two drastically different debonding rates are observed,i.e.,rapid snap-through debonding and more progressive crack propagation.Motivated by the experimental observation,we propose an improved shear-lag model with a trapezoidal-shaped cohesive zone to derive an analytical solution for the decohesion behavior.The theoretical model reveals that the decohesion behavior of the frictional adhesive interface is governed by three dimensionless parameters.Particularly,the dimensionless length of the film essentially determines the decohesion rate;while the other two parameters affect the critical substrate strain to initiate debonding.By fitting the experimental data with the theoretical model,the intrinsic adhesion properties of the two samples are obtained with physically meaningful values.This work offers an analytical solution to describing the decohesion behavior of general thin film/substrate systems with a frictional adhesive interface,which is beneficial for characterizing and optimizing the mechanical properties of various thin film/polymer devices.

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quan- titatively estimate the interfacial energy of the nanostructured multilayer films （NMFs） adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be ~ 5.0 J/m2 for Cu/Cr, ~4.1 J/m2 for Cu/Ta, ~ 2.8 J/m2 for Cu/Mo, ~ 1.1 J/m2 for Cu/Nb, and ~ 1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.

磷化电流密度对A286合金电化学磷化膜组织结构和结合强度的影响

A286合金表面易钝化,通过传统化学磷化方法在其表面难以沉积磷化膜,而电化学磷化可避免钝化膜对磷化反应的抑制作用。因此,研究磷化电流密度对磷化膜组织结构和性能的影响规律很有必要。通过电化学磷化首次在A286合金表面形成了致密、高膜基结合力的磷化膜。利用电化学工作站对不同电流密度下磷化过程中电位-时间(ϕ-t)曲线进行测绘,研究电化学磷化膜生长过程的特点;使用扫描电子显微镜(SEM)观察磷化膜的显微组织形貌;使用能谱仪(EDS)分析磷化膜中不同区域的化学成分;使用X射线衍射仪(XRD)研究磷化膜的物相结构;使用划痕仪测定磷化膜与基体的结合力。结果显示:A286合金电化学磷化膜的沉积模式为逐层生长-堆叠的形式。低电流密度下,磷化膜为单一的Hopeite相,组织结构粗大、疏松,膜基结合力约为6 N。随着磷化电流密度的增加,磷化膜逐渐转变为Zn+Hopeite复相,组织结构细化、致密,膜基结合力提高。当阴极电流密度为160 mA/cm^(2)时,膜基结合力高于60 N。综合可知,磷化电流密度的增加有利于电化学磷化膜的致密化,有利于膜基结合力和耐磨性的提高。

Properties of W/DLC/W-S-C composite films fabricated by magnetron sputtering

A kind of W/DLC/W-S-C composite film was fabricated by magnetron sputtering method.Effects of WSx content on the structure and the adhesion of the composite films were investigated.In addition,tribological behavior of the composite films was studied in the conditions of the ambient air and N2 gas atmosphere by ball-on-disk tester.The results indicate that the composite films show dense and amorphous microstructure.The WCx and WSx compounds are found in amorphous diamond like carbon matrix in the top layers of W-S-C.A proper WSx content is beneficial for improving the adhesion of the composite films.In air atmosphere,the composite films with high C content have better wear resistance and the friction coefficients range from 0.15 to 0.25.In N2 condition,high WSx content is benefit for the wear resistance and the friction coefficients of the composite films range from 0.03 to 0.1.

基于自动化设备的薄膜紧固包装黏合工艺分析与优化

目的基于薄膜紧固包装结构与自动化生产装备,比较选择结构间黏合剂材料,调整设备最优工艺参数,以提高设备生产效率,增加薄膜与瓦楞纸间黏合强度保证包装运输储存稳定性。方法分析薄膜紧固包装自动化设备中对黏合强度的主要影响工艺条件,通过黏合剂种类、涂胶量、覆膜压力、黏合剂温度、时间固化条件单因素试验探究变量对黏合强度影响情况;在此基础上,采用Box-Behnken响应面法优化薄膜紧固包装材料自动化黏合工艺。结果根据材料间黏合强度与高低老化试验比较选用8335封口胶作为薄膜包装胶黏剂材料;黏合强度随涂胶量的增加呈现先线性增长后缓慢下降的趋势,其中当涂胶量为200 g/m2时达到最大值;薄膜与纸板的黏合强度先逐渐增大后迅速减小,辊筒与传送底面间隙为2.4 mm时,黏合强度最大;设备空间大小与生产速度限制时间内,固化时间对黏合强度的影响较小;在适宜的温度内,固化温度越高,黏合强度越好。最后通过响应面试验得到,薄膜紧固包装黏合强度影响因素显著程度从大到小为取胶间隙、覆膜间隙、固化温度。结论响应面法回归预测模型预测值与实际试验值误差为2.16%,说明预测模型可靠,且优化生产工艺参数后薄膜紧固包装较优化前对恶劣运输环境抵抗能力提高,为提高薄膜紧固包装可靠性提供生产参考依据。

基于电气自动化装备的各种不同胶接接头粘接性能研究

以6005A铝合金为基材,采用硅烷聚氨酯胶粘剂制备了对接接头、搭接接头和不同角度的嵌接接头,并对哑铃型胶粘剂试样进行了力学性能测试。结果表明,当温度从-40℃升高至80℃时,不同温度下对接接头、搭接接头和嵌接接头的平均失效强度都呈现逐渐减小的特征;在温度60℃及以下时,胶粘剂搭接接头的强度要高于对接接头。将对接接头和搭接接头相比,在温度-40~80℃时,搭接接头的断裂能高于对接接头;从不同角度接头的断裂能分析,15°接头在不同温度下都具有相对较高的断裂能,且此时的断裂能要明显高于对接接头和搭接接头。

高精度薄厚膜异构HTCC基板制备工艺

针对高温共烧陶瓷(HTCC)基板高平整度、高密度封装需求,提出了一种高精度薄厚膜异构HTCC基板的制备方法,并对其关键工艺进行研究。结合陶瓷基板精密研磨工艺与薄膜制备工艺,该方法在大幅降低原有HTCC基板的平面度、粗糙度的同时,实现HTCC表面精密布线。测量结果表明,薄厚膜HTCC基板的平面度低至15μm,表面布线最小线宽低至10μm,与传统陶瓷基板平面度(30μm)与最小线宽(50μm)相比均有较大改善。在此基础上,研究了不同种子层厚度对薄厚膜异构HTCC基板结合力的影响。结果表明当钛钨层厚度为150 nm时,薄膜层和陶瓷基板结合力高达9.27 gf(1 gf=0.0098 N)。

基于氮化铝HTCC的表面Cu互连制备技术

针对高集成密度、高散热封装外壳发展需求,基于氮化铝(AlN)高温共烧陶瓷(HTCC)多层基板,结合直接镀铜(DPC)工艺,提出了一种薄厚膜相结合的高散热封装基板及其制备方法。重点对氮化铝HTCC与表面铜(Cu)层间的结合力进行研究和优化,通过扫描电子显微镜(SEM)、能谱仪(EDS)和剥离强度测试仪分析和研究了界面的微观结构和力学性能。研究结果表明:与氮化铝/钛钨(TiW)/Cu相比,氮化铝/钛(Ti)/Cu界面的缺陷更少,金属Ti的黏附性能更优,拉脱断裂面在陶瓷基板上。当采用厚度为400 nm的Ti作为黏附层时,表面金属化剥离强度高达592 MPa,实现了高界面结合力,保证了产品封装性能的稳定性。

耐候型聚烯烃粘接胶膜性能研究

通过聚烯烃改性技术分别制备出具有耐候性能和粘接性能的改性聚烯烃材料,再将这些改性聚烯烃材料通过共挤吹膜工艺一体化成型,制备兼具耐候性能和粘接性能的功能性聚烯烃胶膜。对该胶膜的加工成膜、耐候性能和粘接性能进行进一步评估和研究。研究结果表明:胶膜内、中、外三层材料的厚度比例约为28∶31∶41时,三种材料下料、塑化、吹胀成膜等加工性能良好,胶膜横向和纵向的力学性能均良好,对钢板、铝板、镀锌板均有良好的粘接效果。当其作为金属表面涂层使用时,具备一定的耐酸碱腐蚀性能,并且胶膜与金属形成的粘接界面性能稳定可靠,耐气候老化和耐热氧老化性能优异,可作为具有耐候性和粘接功能的金属复合材料涂层使用。

真空热处理对不锈钢表面TiN薄膜结构及性能的影响

为提高不锈钢材料在海洋环境中的耐腐蚀能力,采用磁控溅射技术在304不锈钢表面沉积TiN薄膜,并在不同温度下对其进行真空热处理,研究热处理温度对TiN薄膜结构及性能的影响。结果表明:适当的真空热处理可提高304不锈钢表面TiN薄膜的结晶度及致密性,缓解其残余应力。与未处理薄膜相比,500℃真空热处理后薄膜内部应力可降低87%,与基底的结合强度提高78%,其腐蚀电流密度由2.42×10^(-6)A/cm^(2)降低到4.43×10^(-7)A/cm^(2),腐蚀电位由-0.247 V提高到-0.044 V,耐腐蚀性能明显提升。

聚氨酯压敏胶保护膜剥离强度与稳定性研究

为了解聚氨酯压敏胶保护膜的剥离强度性能变化趋势,从而稳定保护膜的使用状态,对聚氨酯压敏胶保护膜剥离强度进行了室温工艺性能研究,拟通过改变后熟化条件,以及在压敏胶液中添加助剂等方式,研究聚氨酯压敏胶保护膜的剥离强度变化规律,找到加速稳定剥离强度的方法。结果表明,可以通过提高后熟化温度,缩短后熟化时间;也可以通过在压敏胶液配方中加入适量催化助剂,降低保护膜涂布下线剥离强度,加速保护膜剥离强度的稳定,从而提高保护膜的生产效率,缩短保护膜生产工序工艺过程的时间。

包装方式对压敏胶带剥离强度保持率的影响

采用一种3M压敏胶带分别贴合3类离型膜,以3M压敏胶带的180°剥离强度为性能评估指标,考察普通包装方式下,不同离型膜对3M压敏胶带剥离强度随放置时间的变化;考察不同包装方式条件下,胶带随放置时间的剥离强度变化;考察23℃,90%RH下,离型膜对3M压敏胶带剥离强度随放置时间的变化。研究发现,在普通包装下,P53-MBR能够使3M胶带剥离强度保持最佳效果;在真空袋+干燥剂的包装条件下,3M压敏胶带贴合离型膜P53-MBR放置不同的时间后,胶带的剥离强度保持率最高;在23°,90%RH下,搭配P53-MBR对3M胶带的剥离强度影响更小。结果表明,3M压敏胶带较为理想的贮存条件是隔绝空气中的水和氧,P53-MBR是3M压敏胶带搭配最佳的离型膜,这对3M压敏胶加工成品出货具有现实意义。

Amorphous SiO_2 interlayers for deposition of adherent diamond films onto WC-Co inserts

Amorphous Si O2（a-Si O2） films were synthesized on WC-Co substrates with H2 and tetraethoxysilane（TEOS） via pyrolysis of molecular precursor.X-ray diffraction（XRD） pattern shows that silicon-cobalt compounds form at the interface between a-Si O2 films and WC-Co substrates.Moreover,it is observed by transmission electron microscope（TEM） that the a-Si O2 films are composed of hollow mirco-spheroid a-Si O2 particles.Subsequently,the a-Si O2 films are used as intermediate films and chemical vapor deposition（CVD） diamond films are deposited on them.Indentation tests were performed to evaluate the adhesion of bi-layer（a-Si O2 ＋ diamond） films on cemented carbide substrates.And the cutting performance of bi-layer（a-Si O2 ＋ diamond） coated inserts was evaluated by machining the glass fiber reinforced plastic（GFRP）.The results show that a-Si O2 interlayers can greatly improve the adhesive strength of diamond films on cemented carbide inserts;furthermore,thickness of the a-Si O2 interlayers plays a significant role in their effectiveness on adhesion enhancement of diamond films.