西南交大材料成型表面工程期末考试总结由刀豆文库小编整理，希望给你工作、学习、生活带来方便，猜你可能喜欢“西南交通大学期末考试”。
Chapter1 Q1: why surfacing coating? A1: 1.Greatly improve the surface performance, the use efficiency of material, service life of the equipment.2.Saving expensive material, resource, labor, and reduce the cost.3.Different property needed for surface and bulk that only coating can satisfy.Chapter2 Q1: characterization methods of coatings and thin films A1:
r Thickne---optical microscopy Morphology---SEM Composition---XRD Mechanical characterization Hardne –-micro hardne and nana hardne tester(显微硬度仪)
Adhesion---Scratch tester
Q2: Typical surface of solid A1: 1.ideal surface(完美晶格)2.clean surface（表面和内部结构不同，但化学成分相同）
3.actual surface（结构成分都不同）
Q3:Wear A3: abrasion erosion adhesion surface fatigue
Q4: The difference of the mechanism between adhesive and abrasion Wear?
Mechanism of Abrasion :abrasive wear is defined as wear due to hard particles and protuberance forced against and moving along a solid surface.Mechanism of adhesive : adhesive wear is defined as wear by transference of material from a surface to another during a relative motion under load.Particles remove from one surface are either permanently or temporarily to attach to another surface.Chapter3
Q1: what must have for a corrosion to occur in metals? A1: for corrosion occurs in metals, one must have: 1.an electrolyte 2.an area or region on a metallic surface with negative charge 3.another area with positive charge 4.an electrically conductive path between 2 and 3 Q2: Claification and prevention of surface corrosion A2：Uniform corrosion(全面腐蚀，其余全部是部分腐蚀)Galvanic corrosion Pitting corrosion Intergranular corrosion Stre corrosion-cracking
Q3: the differences of the mechanism between intergranular corrosion and SCC? A3:
intergranular corrosion : the type of attack result from the difference of local composition.the
selective diolution of grain boundary or adjacent area attack of the grains themselves.SCC: SCC is a cracking phenomenon occurs in an susceptible alloy caused by the conjunction action of the surface tensile stre and the presence of a special corrosion environment.SCC形成的三个必要条件: 1． 促裂环境
2． 应力腐蚀敏感合金 3． 超阈值应力
Q4:Give some example for corrosion resistant coating? A4: 1.Sacrificial coating 2.Barrier coating 3.Various polymer coating.Chapter4 Key point:
Dimensions:
0-D:powers
1-D:multi-layer films or wires 2-D:nano-structureed coating 3-D:nano-bulk materials
Q1: why hall-petch formula not suitable for the metal with the size of
Gy=G0+ky/d1/2（此处用G代替代尔塔）
the H-P relation is based on a physical model of dislocation pilling.For metal size below 20nm, material may : 1.lack of space for dislocation pilling up 2.absorbtion dislocation to G.b may change the g.b nature 3.soften effects of deformation for very high density of grain boundary
Q2: why does melting point decrease of nanometal? A2: Grainsize-D-----surface area-U-----surface energy-U-----atomic bonds loen-----le energy needed-----thermal point-D(D表示下降，U表示上升)
Q3： Application A3:
Disk or sensitive sensor…
Chapter5 Key point
1.制备纳米材料的几种方法：球磨法，气相沉积法，磁控溅射法，溶胶凝胶法。
气相沉积法：0.向腔体内充入惰性气体
1.前躯体从蒸发源蒸发 2.蒸汽在冷凝棒上凝结
3.收集在冷凝棒上凝结材料。
磁控溅射：在正负极板间施加高压电场，激发出电子轰向靶材，同时在极板间施加交变磁场，使得一次电子左右摆动产生更多的二次电子，同时减弱一次电子能量，使得不会对靶材造成损伤同时将靶材轰击至基材。
溶胶凝胶法：
1.用有机物或金属醇盐配置前躯体溶液。
2.经水解缩合反应之后产生溶胶，然后进一步反应得到网状结构凝胶 3.干燥烧结，便可以得到分子乃至纳米亚结构的材料
Flame temperature/K Flame velocity(m/s)Particle velocity(m/s)Bonding strength(MPa)Porosity(%)Thickne(um)cost FS 3000-3500 80-100 20-80 >15 10-20 100-2500 low
AS 4000-6100 150 20-300 >10 10-20 100-2000 low
APS 14000-28000 200-1200 30-800 50-80 1-7 300-1000 high
D-gun 4500 800-1200 750-1000 >70 0.5-2
HVOF 2500-3000 1600-2000 ~1000 90
Chapter6
Motheds : AS(速度快，效率高，质量低，适合喷涂大件)
FS
APS（万能喷涂法）
D-Gun（钴基碳化物）
HVOF（钴基碳化物）适合喷涂钴基碳化物的方法？ D-gun，HVOF
D-gun： 1.将燃料气体注入爆炸腔内
2.将氮气和粉末注入腔体
3.点燃气体，爆炸产生高速气体将粉末喷涂在基材上
4.氮气清除腔体
为什么用这种方法喷涂钴基碳化物？
爆炸喷涂时粒子飞行速度快，高温停留时间短，不容易造成碳的分解，降低膜层性能。所以采用这种方法。
Chapter7 Q1:Why not pure ZrO2 coating? A1: the crystalline transformation of ZrO2 in high temperature is accompanied with a large irreversible volume change.Thermal stre will cause the coating broken off.Q2:Solution for above question A2: CaO has cubic structure which changes the monocline crystal of ZrO2 into cubic crystal structure.Y2O3 can make ZrO2 form a stable or semi-stable crystal structure at high temperature.With T increase, monoclinic crystal change to tetragonal crystal with the volume shrinkage , while the cubic crystal volume expand.And volume shrinkage are counteracted by the volume expansion.Chapter 8 Surface cleaning 可以用有机溶剂或者碱洗或者激光清除。
Shaping
Shaping is also neceary to avoid sharp angles or sharp ends where it is difficult to spray a coating on.Activation
Abrasive grit blasting An increase in the roughne result in an increase in the adhesion.喷砂相关的参数工艺 时间/压力/角度等。
Masking This is not neceary for spraying.If you have to do so , masking should also be applied at the surface activation stage.Chapter9 后处理 1热处理
1.spark plasma sintering 2.microwave sintering 3.laser sintering 2.封孔
用有机物质或者熔融金属等，将膜层表面微孔密封提升抗腐蚀性能 3.精加工
进一步进行加工至所需精度和表面粗糙度
粒子数反转
To make a stimulated radiation phenomenon, the number of particles in high-energy level must be more than that of low-energy.And this kind of distribution is called population inversion
激光也分波长ppt中介绍了10微米和1微米的。焊接金属物质可以使用1微米的。
