The effect of ZrO2 content on the performance of vitrified bond was discussed. The results showed that when the ZrO2 content was less than 2 mol%, Zr4＋ could enter into the glassy network as mending nets and agglomer...The effect of ZrO2 content on the performance of vitrified bond was discussed. The results showed that when the ZrO2 content was less than 2 mol%, Zr4＋ could enter into the glassy network as mending nets and agglomeration composition. In this case, with the increasing of ZrO2, the vitrified bond＇s bending strength increased and the expansion coefficient decreased. It was also found that the wetting angle between the vitrified bond and diamond got small because Zr4＋ was enriched on diamond surface. When ZrO2 content was more than 2 mol%, a part of ZrO2 existing in vitrified bond as ZrO2 particles played the role in nucleating agents and promoting the separation of spodttrnene. When ZrO2 content was 3 mol%, the bending strength of the vitrified bond reached its maximum of 128 MPa and the wetting angle with the diamond reached its minimum of 37.6°.展开更多
In this work, a kind of new vitrified bond based on Li2O-Al2O3-SiO2 glass ceramics was used to bond the diamond grains, which is made into grinding wheel and the cylindrical grinding process of polycrystalline diamond...In this work, a kind of new vitrified bond based on Li2O-Al2O3-SiO2 glass ceramics was used to bond the diamond grains, which is made into grinding wheel and the cylindrical grinding process of polycrystalline diamond compacts （PDCs） by using the new vitrified bond diamond grinding wheel was discussed. Several factors which influence the properties of grinding wheel such as amount of vitrified bond and the kinds and amount of stuff in grinding wheel were also investigated. It was found that the new vitrified bond can firmly combine diamond grains, when there are only diamonds and vitrified bond in the structure of grinding wheel, the longevity of the grinding wheel is about 2.5-3 times as that of resin bond grinding wheel for processing PDCs. The grinding size precision of PDCs can be improved from 4-0.03 mm to 4-0.01 mm because of larger Young＇s modulus of vitrified bond than resin bond. The grinding time of a PDC product can be 1.75-2.0 min from 3.25-3.5 min, so this kind of grinding wheel can save much time for processing PDCs. Also, there is hardly noise when using this new vitrified bond diamond grinding wheel to process PDCs. The amount of vitrified bond in grinding wheel influences the longevity of grinding wheel. When the size of diamond grains is 90-107 μm, the optimal amount of vitrified bond in grinding wheel is 21% （wt pct）. When the amount of vitrified bond exceeds 21%, there are many pores in grinding block, which will decrease the longevity of grinding wheel. The existence of addition stuff such as Al2O3 or SiC can reduce the longevity of grinding wheel.展开更多
In order to develop high-performance diamond wheels,the vitrified bond with different contents of Li2O addition and corresponding diamond composites were prepared.The experimental results show that the addition of a s...In order to develop high-performance diamond wheels,the vitrified bond with different contents of Li2O addition and corresponding diamond composites were prepared.The experimental results show that the addition of a small content of Li2O leads the formation of the mullite phase in vitrified bond.When the Li2O content is 3wt%,the mullite content in the vitrified bond reaches the maximum.Whereas,the vitrified bond turns into a pure glass phase when the Li2O content further increases to 5wt%.The softening temperature of vitrified bond,wetting angle between the vitrified bond and the diamond film decrease with the increasing of the Li2O content.The softening point of the vitrified bond with 5wt% Li2O is 537 ℃ and the contact angle is 32°,which are 44 ℃ and 44° lower than those of the sample without Li2O.The CTE (coefficient of thermal expansion),the flexural strength and hardness of the diamond composite sample first increase and then decrease with the increasing of the Li2O content.When the Li2O addition is 3wt%,the flexural strength and hardness of the composites reaches the maximum values of 93 MPa and 98 HRB,respectively,which are 43.1% and 12.6% higher than those of the sample without Li2O.展开更多
Influence of aluminum addition on the structures and properties of SiO_2-B_2O_3-Al_2O_3-CaO vitrified bond at low sintering temperature and high strength was discussed. FTIR and XRD analyses were used to characterize ...Influence of aluminum addition on the structures and properties of SiO_2-B_2O_3-Al_2O_3-CaO vitrified bond at low sintering temperature and high strength was discussed. FTIR and XRD analyses were used to characterize the structures of the basic vitrified bond with different contents of aluminum. The bending strength and the thermal expansion coefficients were also tested. Meanwhile, the microstructures of composite specimens at sintering temperature of 660 ℃ were observed by scanning electron microscope（SEM）. The experimental results showed that the properties of vitrified bond with 1wt% aluminum were improved significantly, where the bending strength, Rockwell hardness, and thermal expansion coefficient of the vitrified bond reached 132 MPa, 63 HRB, and 6.73×10^（-6） ℃^（-1）, respectively.展开更多
基金Funded by National Natural Science Foundation of China(NSFC)(Nos.51172169,51372180)Hunan Provincial Natural Science Foundation of China(No.11JJ3052)Fundamental Research Funds for the Central Universities(No.135201008)
文摘The effect of ZrO2 content on the performance of vitrified bond was discussed. The results showed that when the ZrO2 content was less than 2 mol%, Zr4＋ could enter into the glassy network as mending nets and agglomeration composition. In this case, with the increasing of ZrO2, the vitrified bond＇s bending strength increased and the expansion coefficient decreased. It was also found that the wetting angle between the vitrified bond and diamond got small because Zr4＋ was enriched on diamond surface. When ZrO2 content was more than 2 mol%, a part of ZrO2 existing in vitrified bond as ZrO2 particles played the role in nucleating agents and promoting the separation of spodttrnene. When ZrO2 content was 3 mol%, the bending strength of the vitrified bond reached its maximum of 128 MPa and the wetting angle with the diamond reached its minimum of 37.6°.
文摘In this work, a kind of new vitrified bond based on Li2O-Al2O3-SiO2 glass ceramics was used to bond the diamond grains, which is made into grinding wheel and the cylindrical grinding process of polycrystalline diamond compacts （PDCs） by using the new vitrified bond diamond grinding wheel was discussed. Several factors which influence the properties of grinding wheel such as amount of vitrified bond and the kinds and amount of stuff in grinding wheel were also investigated. It was found that the new vitrified bond can firmly combine diamond grains, when there are only diamonds and vitrified bond in the structure of grinding wheel, the longevity of the grinding wheel is about 2.5-3 times as that of resin bond grinding wheel for processing PDCs. The grinding size precision of PDCs can be improved from 4-0.03 mm to 4-0.01 mm because of larger Young＇s modulus of vitrified bond than resin bond. The grinding time of a PDC product can be 1.75-2.0 min from 3.25-3.5 min, so this kind of grinding wheel can save much time for processing PDCs. Also, there is hardly noise when using this new vitrified bond diamond grinding wheel to process PDCs. The amount of vitrified bond in grinding wheel influences the longevity of grinding wheel. When the size of diamond grains is 90-107 μm, the optimal amount of vitrified bond in grinding wheel is 21% （wt pct）. When the amount of vitrified bond exceeds 21%, there are many pores in grinding block, which will decrease the longevity of grinding wheel. The existence of addition stuff such as Al2O3 or SiC can reduce the longevity of grinding wheel.
基金Funded by the Zhejiang Provincial Key Research and Development Project(No.2018C01076)。
文摘In order to develop high-performance diamond wheels,the vitrified bond with different contents of Li2O addition and corresponding diamond composites were prepared.The experimental results show that the addition of a small content of Li2O leads the formation of the mullite phase in vitrified bond.When the Li2O content is 3wt%,the mullite content in the vitrified bond reaches the maximum.Whereas,the vitrified bond turns into a pure glass phase when the Li2O content further increases to 5wt%.The softening temperature of vitrified bond,wetting angle between the vitrified bond and the diamond film decrease with the increasing of the Li2O content.The softening point of the vitrified bond with 5wt% Li2O is 537 ℃ and the contact angle is 32°,which are 44 ℃ and 44° lower than those of the sample without Li2O.The CTE (coefficient of thermal expansion),the flexural strength and hardness of the diamond composite sample first increase and then decrease with the increasing of the Li2O content.When the Li2O addition is 3wt%,the flexural strength and hardness of the composites reaches the maximum values of 93 MPa and 98 HRB,respectively,which are 43.1% and 12.6% higher than those of the sample without Li2O.
基金Funded by the National“Twelfth Five-Year”Plan for Science&Technology Support of China(2012BAA08B00)
文摘Influence of aluminum addition on the structures and properties of SiO_2-B_2O_3-Al_2O_3-CaO vitrified bond at low sintering temperature and high strength was discussed. FTIR and XRD analyses were used to characterize the structures of the basic vitrified bond with different contents of aluminum. The bending strength and the thermal expansion coefficients were also tested. Meanwhile, the microstructures of composite specimens at sintering temperature of 660 ℃ were observed by scanning electron microscope（SEM）. The experimental results showed that the properties of vitrified bond with 1wt% aluminum were improved significantly, where the bending strength, Rockwell hardness, and thermal expansion coefficient of the vitrified bond reached 132 MPa, 63 HRB, and 6.73×10^（-6） ℃^（-1）, respectively.
