磨削金刚石复合片用陶瓷金刚石砂轮结合剂的制备与性能研究
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摘要
本文针对树脂结合剂金刚石砂轮在磨削金刚石复合片中存在的磨削效率低、加工复合片尺寸一致性差、磨削噪音大等问题，结合陶瓷结合剂金刚石砂轮的特点，旨在能研制出金刚石砂轮用陶瓷结合剂代替树脂结合剂克服这些缺点。本文对陶瓷结合剂金刚石砂轮的金刚石磨料选择、结合剂原料选择、结合剂制备工艺、结合剂应用等方面进行了研究，讨论了在金刚石复合片的外圆磨削中用陶瓷结合剂金刚石砂轮代替树脂结合剂金刚石砂轮的可行性，并取得一定成效。其主要的研究工作及试验结果概括如下：
1．进行了金刚石磨料的高温稳定性试验，发现在高于700℃时，金刚石磨料在空气气氛中会发生氧化反应，使金刚石磨料受到损害；金刚石磨料高温下的热损害程度与金刚石磨料的品级、粒度有关，相同温度下，品级越低、粒度越细，金刚石磨料受到的热损害程度越高；而陶瓷结合剂金刚石试块在埋入石英砂中、空气气氛下，750℃时对金刚石磨料本身的热损害很小。结合金刚石磨料的热稳定性及金刚石复合片磨削的特点选用Ⅱ型金刚石作为磨复合片用陶瓷金刚石砂轮的磨料。
2．根据金刚石磨料的热稳定性，确定了砂轮的烧成温度及结合剂的耐火度范围，运用氧化物的生成自由能原理对几种氧化物在砂轮烧成温度时与金刚石磨料的反应情况进行分析，确定了结合剂的化学组成。根据玻璃结构理论确定了结合剂中各成分的含量，确定了结合剂配方。
3．讨论了结合剂的制备工艺。本文采用冶炼法制备陶瓷结合剂，确定了结合剂制备的工艺流程，讨论了不同升温曲线对冶炼结合剂性能的影响，发现只有当结合剂原料中的结晶水及易分解物质在其分解温度分解完全后再升至冶炼温度，得到的结合剂才性能稳定；并对结合剂进行性能测试，冶炼的结合剂耐火度低(580-630℃)、热膨胀系数小(7.2-8.0~*10~(-6)℃~(-1))、抗折强度高(45-58MPa)、对金刚石磨粒把持强度大，适合制造磨削金刚石复合片用陶瓷结合剂金刚石砂轮。
4．进行了结合剂应用试验，用冶炼的结合剂制造磨削复合片金刚石砂轮，进行磨削金刚石复合片试验。在磨削过程中，发现复合片磨削主要是磨去复合片外圆上多余的金刚石，由于金刚石非常坚硬，当用树脂结合剂砂轮磨削时，由于树脂结合剂金刚石砂轮为保证砂轮的耐用度，一般做得都很密实，基本无气孔，因此磨削时磨削力特别大，对磨床主轴的伤害很大；而且砂轮很不锋利，进刀大时砂轮会让刀，而且发出嚣叫声；磨削效率很低。而陶瓷结合剂金刚石砂轮由于有气孔，砂轮的自
锐性很好，对磨床主轴的伤害小;砂轮锋利，磨削效率高;磨削时不让刀，磨出复
合片尺寸一致性好。另外磨削复合片时磨削区温度很高，树脂不耐高温，因此在磨
削区树脂会变软，对金刚石磨料的把持强度降低，砂轮消耗快;陶瓷结合剂则不存
在这一问题。砂轮磨削时噪音很小，几乎听不到磨削声音。陶瓷结合剂金刚石砂轮
磨削金刚石复合片的优点是磨削效率高、磨削的复合片尺寸一致性好、磨削噪音低、
对磨床主轴的损害小。
5.存在问题:从与树脂结合剂金刚石砂轮磨削情况对比可以看出，陶瓷结合剂
金刚石砂轮磨削单件复合片的砂轮直接成本比树脂结合剂金刚石砂轮还略高一些，
这说明我们的结合剂对金刚石磨料的把持强度还需提高，今后应在改善结合剂性
能，如降低结合剂的膨胀系数、增加结合剂对金刚石磨粒的把持强度等的研究试验，
以提高陶瓷结合剂金刚石砂轮的磨削寿命，降低加工成本，争取能用于工业生产中。
This paper aimed at the resin bond diamond grinding wheel' disadvantage such as the lower grinding efficiency, the higher noise, the worse uniformity of the grinded Polycrystalline Diamond Compact(PDC) size, and integrated the characteristics of vitrified bond diamond grinding wheel , discussed the feasibility of vitrified bond diamond grinding wheel instead resin bond diamond grinding wheel to grind PDC. We researched the choice of diamond, the materials' choice of vitrified bond, the manufacturing process of vitrified bond and the experiment of using vitrified bond diamond grinding wheel to PDC . We have done some experiment and research work about this. Now it's abstracted the following:
The first is the stability of the diamond in high temperature .We find that when the temperature exceed 700 centigrade, the diamond begin to oxidize in the air, the degree of oxidization of the diamond is related to its quality and its grain size. The lower quality or the finer size the diamond is, the higher degree of oxidization. But when the vitrified diamond stone is buried into quartz sand ,In 750 centigrade, the damage to diamond is much smaller. Integrated the thermal stability of diamond and the characteristics of grinding PDC, we chose the II diamond to be the vitrified bond grinding wheel's abrasive.
The second we defined the fastness to fire of the vitrified bond and the sintering temperature based on diamond thermal stability .we also used the formation enthalpy of the oxide to analysis the chemical reaction situation between the oxide and the diamond at the sintering temperature, the theory of glass structure to define the prescription of the bond.
The third is the manufacturing process of vitrified. In this paper the vitrified bond is made by smelting. We discussed that different smelting curve influenced on the property of the vitrified bond, we found only when all the steam of crystallization and the decomposition gas is got rid of at a lower temperature, the properties of the vitrified bond can be stabilized. We also examined the properties of the smelted vitrified bond. The result of the examination : the fastness to fire of the bond is 580-630 centigrade, the coefficient of thermal expansion about the bond is 7.2-8.0 10-6 -1. These
properties can meet the diamond's sintering demand. The bending strength of the diamond stone which is made of this bond is very high(45-58Mpa).
The forth is the application of vitrified bond, including the grinding wheel's manufacturing process and the grinding experiment. We find the resin bond's still binding strength to the abrasive is not much lower than the vitrified bond. But its lifetime in grinding PDC is much shorter. The main reason we thought is that during the grinding process, the instantaneous temperature in grinding area is very high(might be 500 癈), then the resin can become soft and the binding strength between the resin and abrasive is very weak ,so the decrement of the resin bond grinding wheel is very fast. In the other hand to increase its lifetime the resin bond grinding wheel is made very dense, so the grinding force is very large and the damage to the grinder's main shaft is very large, but for the vitrified bond grinding wheel, this circumstance doesn't exist.
Through the grinding experiment, we've optimized the prescription of the v-bond and grinding wheel. The advantage of using v-bond diamond grinding wheel to grind PDC is the higher grinding efficiency, the better uniformity of PDC size and grinding noise. But the grinding cost of using v-bond diamond grinding wheel is a bit higher than the resin bond one.
Next we will do more research work in the bond prescription in order to decrease the coefficient of thermal expansion, enlarge the binding strength between the vitrified bond and abrasive and improve the lifetime of vitrified bond grinding wheel.
1．进行了金刚石磨料的高温稳定性试验，发现在高于700℃时，金刚石磨料在空气气氛中会发生氧化反应，使金刚石磨料受到损害；金刚石磨料高温下的热损害程度与金刚石磨料的品级、粒度有关，相同温度下，品级越低、粒度越细，金刚石磨料受到的热损害程度越高；而陶瓷结合剂金刚石试块在埋入石英砂中、空气气氛下，750℃时对金刚石磨料本身的热损害很小。结合金刚石磨料的热稳定性及金刚石复合片磨削的特点选用Ⅱ型金刚石作为磨复合片用陶瓷金刚石砂轮的磨料。
2．根据金刚石磨料的热稳定性，确定了砂轮的烧成温度及结合剂的耐火度范围，运用氧化物的生成自由能原理对几种氧化物在砂轮烧成温度时与金刚石磨料的反应情况进行分析，确定了结合剂的化学组成。根据玻璃结构理论确定了结合剂中各成分的含量，确定了结合剂配方。
3．讨论了结合剂的制备工艺。本文采用冶炼法制备陶瓷结合剂，确定了结合剂制备的工艺流程，讨论了不同升温曲线对冶炼结合剂性能的影响，发现只有当结合剂原料中的结晶水及易分解物质在其分解温度分解完全后再升至冶炼温度，得到的结合剂才性能稳定；并对结合剂进行性能测试，冶炼的结合剂耐火度低(580-630℃)、热膨胀系数小(7.2-8.0~*10~(-6)℃~(-1))、抗折强度高(45-58MPa)、对金刚石磨粒把持强度大，适合制造磨削金刚石复合片用陶瓷结合剂金刚石砂轮。
4．进行了结合剂应用试验，用冶炼的结合剂制造磨削复合片金刚石砂轮，进行磨削金刚石复合片试验。在磨削过程中，发现复合片磨削主要是磨去复合片外圆上多余的金刚石，由于金刚石非常坚硬，当用树脂结合剂砂轮磨削时，由于树脂结合剂金刚石砂轮为保证砂轮的耐用度，一般做得都很密实，基本无气孔，因此磨削时磨削力特别大，对磨床主轴的伤害很大；而且砂轮很不锋利，进刀大时砂轮会让刀，而且发出嚣叫声；磨削效率很低。而陶瓷结合剂金刚石砂轮由于有气孔，砂轮的自
锐性很好，对磨床主轴的伤害小;砂轮锋利，磨削效率高;磨削时不让刀，磨出复
合片尺寸一致性好。另外磨削复合片时磨削区温度很高，树脂不耐高温，因此在磨
削区树脂会变软，对金刚石磨料的把持强度降低，砂轮消耗快;陶瓷结合剂则不存
在这一问题。砂轮磨削时噪音很小，几乎听不到磨削声音。陶瓷结合剂金刚石砂轮
磨削金刚石复合片的优点是磨削效率高、磨削的复合片尺寸一致性好、磨削噪音低、
对磨床主轴的损害小。
5.存在问题:从与树脂结合剂金刚石砂轮磨削情况对比可以看出，陶瓷结合剂
金刚石砂轮磨削单件复合片的砂轮直接成本比树脂结合剂金刚石砂轮还略高一些，
这说明我们的结合剂对金刚石磨料的把持强度还需提高，今后应在改善结合剂性
能，如降低结合剂的膨胀系数、增加结合剂对金刚石磨粒的把持强度等的研究试验，
以提高陶瓷结合剂金刚石砂轮的磨削寿命，降低加工成本，争取能用于工业生产中。
This paper aimed at the resin bond diamond grinding wheel' disadvantage such as the lower grinding efficiency, the higher noise, the worse uniformity of the grinded Polycrystalline Diamond Compact(PDC) size, and integrated the characteristics of vitrified bond diamond grinding wheel , discussed the feasibility of vitrified bond diamond grinding wheel instead resin bond diamond grinding wheel to grind PDC. We researched the choice of diamond, the materials' choice of vitrified bond, the manufacturing process of vitrified bond and the experiment of using vitrified bond diamond grinding wheel to PDC . We have done some experiment and research work about this. Now it's abstracted the following:
The first is the stability of the diamond in high temperature .We find that when the temperature exceed 700 centigrade, the diamond begin to oxidize in the air, the degree of oxidization of the diamond is related to its quality and its grain size. The lower quality or the finer size the diamond is, the higher degree of oxidization. But when the vitrified diamond stone is buried into quartz sand ,In 750 centigrade, the damage to diamond is much smaller. Integrated the thermal stability of diamond and the characteristics of grinding PDC, we chose the II diamond to be the vitrified bond grinding wheel's abrasive.
The second we defined the fastness to fire of the vitrified bond and the sintering temperature based on diamond thermal stability .we also used the formation enthalpy of the oxide to analysis the chemical reaction situation between the oxide and the diamond at the sintering temperature, the theory of glass structure to define the prescription of the bond.
The third is the manufacturing process of vitrified. In this paper the vitrified bond is made by smelting. We discussed that different smelting curve influenced on the property of the vitrified bond, we found only when all the steam of crystallization and the decomposition gas is got rid of at a lower temperature, the properties of the vitrified bond can be stabilized. We also examined the properties of the smelted vitrified bond. The result of the examination : the fastness to fire of the bond is 580-630 centigrade, the coefficient of thermal expansion about the bond is 7.2-8.0 10-6 -1. These
properties can meet the diamond's sintering demand. The bending strength of the diamond stone which is made of this bond is very high(45-58Mpa).
The forth is the application of vitrified bond, including the grinding wheel's manufacturing process and the grinding experiment. We find the resin bond's still binding strength to the abrasive is not much lower than the vitrified bond. But its lifetime in grinding PDC is much shorter. The main reason we thought is that during the grinding process, the instantaneous temperature in grinding area is very high(might be 500 癈), then the resin can become soft and the binding strength between the resin and abrasive is very weak ,so the decrement of the resin bond grinding wheel is very fast. In the other hand to increase its lifetime the resin bond grinding wheel is made very dense, so the grinding force is very large and the damage to the grinder's main shaft is very large, but for the vitrified bond grinding wheel, this circumstance doesn't exist.
Through the grinding experiment, we've optimized the prescription of the v-bond and grinding wheel. The advantage of using v-bond diamond grinding wheel to grind PDC is the higher grinding efficiency, the better uniformity of PDC size and grinding noise. But the grinding cost of using v-bond diamond grinding wheel is a bit higher than the resin bond one.
Next we will do more research work in the bond prescription in order to decrease the coefficient of thermal expansion, enlarge the binding strength between the vitrified bond and abrasive and improve the lifetime of vitrified bond grinding wheel.
引文
1．郭志猛 等编著 超应材料与工具 冶金工业出版社
2．徐为瑜 著 普通磨料概论 河南教育出版社
3．大连理工大学无机化学教研室 无机化学(上、下) 高等教育出版社
4．刘蒲生 等编著 磨具选择与使用 机械工业出版社
5．黄秉麟 等编著 陶瓷磨具制造 机械工业委员会机床工具工业局
6．李志宏 主编 陶瓷磨具制造 中国标准出版社
7．华南工学院等校合编 陶瓷工艺学 中国建筑工业出版社
8．池震宇 编著 磨削加工与磨具选择 兵器工业出版社
9．李伯民 等编著 实用磨削技术 机械工业出版社
10．陈巳珊 朱山民编著 金刚石磨具制造 机械工业部机床工业工业局
11．傅献采 沈文霞等编 物理化学 高等教育出版社
12．浙江大学等编 硅酸盐物理化学 中国建筑工业出版社
13．[日]吉木文平 非金属矿物工学 科学出版社
14．陈福恒等编 国外磨具制造与应用译文集—资料汇编 第二砂轮厂挡案信息处情报翻译科
2．徐为瑜 著 普通磨料概论 河南教育出版社
3．大连理工大学无机化学教研室 无机化学(上、下) 高等教育出版社
4．刘蒲生 等编著 磨具选择与使用 机械工业出版社
5．黄秉麟 等编著 陶瓷磨具制造 机械工业委员会机床工具工业局
6．李志宏 主编 陶瓷磨具制造 中国标准出版社
7．华南工学院等校合编 陶瓷工艺学 中国建筑工业出版社
8．池震宇 编著 磨削加工与磨具选择 兵器工业出版社
9．李伯民 等编著 实用磨削技术 机械工业出版社
10．陈巳珊 朱山民编著 金刚石磨具制造 机械工业部机床工业工业局
11．傅献采 沈文霞等编 物理化学 高等教育出版社
12．浙江大学等编 硅酸盐物理化学 中国建筑工业出版社
13．[日]吉木文平 非金属矿物工学 科学出版社
14．陈福恒等编 国外磨具制造与应用译文集—资料汇编 第二砂轮厂挡案信息处情报翻译科