公开(公告)号：US5091347A

公开(公告)日：1992-02-25

申请号：US567889

申请日：1990-08-15

申请人： Aleksander J. Pyzik ,  Barbara M. Pyzik

发明人： Aleksander J. Pyzik ,  Barbara M. Pyzik

IPC分类号： C04B35/584 ,  C04B35/593 ,  C04B35/645 ,  C04B35/80 ,  C04B35/81

CPC分类号： C04B35/645 ,  C04B35/593 ,  C04B35/806

摘要： Prepare a self-reinforced silicon nitride ceramic body of high fracture toughness by hot-pressing a powder mixture containing silicon nitride and three other components under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. The other components are silicon dioxide as a densification aid, a conversion aid such as yttrium oxide and a compound, such as calcium oxide, which enhances growth of .beta.-silicon nitride whiskers. The resultant silicon nitride ceramic has a .beta.-silicon nitride cyrstalline phase, at least 20 volume percent of which is in the form of whiskers or elongated grains having an average aspect ratio of at least about 2.5, and a glassy second phase. The glassy phase contains the silicon dioxide, the conversion aid and the compound which enhances growth of .beta.-silicon nitride whiskers. The glassy phase may also include a minor amount of aluminum nitride or boron nitride.

公开(公告)号：US5160508A

公开(公告)日：1992-11-03

申请号：US826315

申请日：1992-01-24

申请人： Aleksander J. Pyzik ,  Harold E. Rossow ,  Douglas B. Schwarz ,  Donald R. Beaman ,  Barbara M. Pyzik ,  William J. Dubensky

发明人： Aleksander J. Pyzik ,  Harold E. Rossow ,  Douglas B. Schwarz ,  Donald R. Beaman ,  Barbara M. Pyzik ,  William J. Dubensky

IPC分类号： C04B35/593 ,  C04B35/645 ,  C04B35/80

CPC分类号： C04B35/593 ,  C04B35/645 ,  C04B35/806

摘要： A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powder mixture containing silicon nitride, a densification aid such as sodium oxide, a conversion aid such as lanthanum oxide and a compound, such as gallium oxide, which enhances growth of .beta.-silicon nitride whiskers-under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. A novel silicon nitride ceramic of high fracture toughness and high fracture strength is disclosed comprising a .beta.-silicon nitride crystalline phase wherein at least about 20 volume percent of the phase is in the form of whiskers having an average aspect ratio of at least about 2.5; a glassy second phase containing the densificaton aid, the conversion aid, the compound which enhances growth of .beta.-silicon nitride whiskers, and an amount of silica; and not greater than about 10 weight percent of the total weight as other phases. The glassy phase may also include a minor amount, e.g., up to 5.0 weight percent, based upon total weight of the ceramic, of aluminum nitride or boron nitride. The glassy phase optionally includes an amount of a secondary reinforcing material such as silicon carbide whiskers.

摘要翻译： 一种制备高断裂韧性的自增强氮化硅陶瓷体的方法，包括热压含有氮化硅的粉末混合物，致密化助剂例如氧化钠，转化助剂如氧化镧和化合物如氧化镓 ，其增强了β-硅氮化物晶须的生长 - 在使得具有高纵横比的β-硅氮化物晶须的致密化和原位形成的条件下。 公开了一种具有高断裂韧性和高断裂强度的新型氮化硅陶瓷，其包括β-氮化硅结晶相，其中该相的至少约20体积百分数为晶须的形式，其平均纵横比为至少约2.5; 含有致密助剂的玻璃质第二相，转化助剂，增强β-硅氮化物晶须生长的化合物和一定量的二氧化硅; 并且不大于作为其它相的总重量的约10重量％。 玻璃相还可以包括少量，例如，基于陶瓷的总重量，至多5.0重量％的氮化铝或氮化硼。 玻璃相任选地包括一定量的第二增强材料，例如碳化硅晶须。

公开(公告)号：US5021372A

公开(公告)日：1991-06-04

申请号：US398801

申请日：1989-08-25

申请人： Aleksander J. Pyzik ,  Douglas B. Schwarz ,  Harold E. Rossow ,  Donald R. Beaman ,  Barbara M. Pyzik ,  William J. Dubensky

发明人： Aleksander J. Pyzik ,  Douglas B. Schwarz ,  Harold E. Rossow ,  Donald R. Beaman ,  Barbara M. Pyzik ,  William J. Dubensky

IPC分类号： C04B35/593 ,  C04B35/645 ,  C04B35/80

CPC分类号： C04B35/645 ,  C04B35/593 ,  C04B35/806

摘要： A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powder mixture containing silicon nitride, a densification aid such as sodium oxide, a conversion aid such as lanthanum oxide and a compound, such as gallium oxide, which enhances growth of .beta.-silicon nitride whiskers-under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. A novel silicon nitride ceramic of high fracture toughness and high fracture strength is disclosed comprising a .beta.-silicon nitride crystalline phase wherein at least about 20 volume percent of the phase is in the form of whiskers having an average aspect ratio of at least about 2.5; a glassy second phase containing the densification aid, the conversion aid, the compound which enhances growth of .beta.-silicon nitride whiskers, and an amount of silica; and not greater than about 10 weight percent of the total weight as other phases. The glassy phase may also include a minor amount, e.g., up to 5.0 weight percent, based upon total weight of the ceramic, of aluminum nitride or boron nitride.

摘要翻译： 一种制备高断裂韧性的自增强氮化硅陶瓷体的方法，包括热压含有氮化硅的粉末混合物，致密化助剂例如氧化钠，转化助剂如氧化镧和化合物如氧化镓 ，其增强了β-硅氮化物晶须的生长 - 在使得具有高纵横比的β-硅氮化物晶须的致密化和原位形成的条件下。 公开了一种具有高断裂韧性和高断裂强度的新型氮化硅陶瓷，其包括β-氮化硅结晶相，其中该相的至少约20体积百分数为晶须的形式，其平均纵横比为至少约2.5; 含有致密化助剂的玻璃质第二相，转化助剂，增强β-硅氮化物晶须生长的化合物和一定量的二氧化硅; 并且不大于作为其它相的总重量的约10重量％。 玻璃相还可以包括少量，例如，基于陶瓷的总重量，至多5.0重量％的氮化铝或氮化硼。

公开(公告)号：US5118645A

公开(公告)日：1992-06-02

申请号：US572823

申请日：1990-08-24

申请人： Aleksander J. Pyzik ,  Harold E. Rossow ,  Douglas B. Schwarz ,  Donald R. Beaman ,  Barbara M. Pyzik ,  William J. Dubensky

发明人： Aleksander J. Pyzik ,  Harold E. Rossow ,  Douglas B. Schwarz ,  Donald R. Beaman ,  Barbara M. Pyzik ,  William J. Dubensky

IPC分类号： B23P15/28 ,  C04B35/584 ,  C04B35/593 ,  C04B35/645 ,  C04B35/80

CPC分类号： C04B35/645 ,  C04B35/593 ,  C04B35/806

摘要： A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powdcer mixture containing silicon nitride, a densification aid such as sodium oxide, a conversion aid such as lanthanum oxide and a compound, such as gallium oxide, which enhances growth of .beta.-silicon nitride whiskers-under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. A novel silicon nitride ceramic of high fracture toughness and high fracture strength is disclosed comprising a .beta.-silicon nitride crystalline phase wherein at least about 20 volume percent of the phase is in the form of whiskers having an average aspect ratio of at least about 2.5; a glassy second phase containing the densification aid, the conversion aid, the compound which enhances growth of .beta.-silicon nitride whiskers, and an amount of silica; and not greater than about 10 weight percent of the total weight as other phases. The glassy phase may also include a minor amount, e.g., up to 5.0 weight percentg, based upon total weight of the ceramic, of aluminum nitride or boron nitride. The glassy phase optionally includes an amount of a secondary reinforcing material such as silicon carbide whiskers.

摘要翻译： 一种制备高断裂韧性的自增强氮化硅陶瓷体的方法，包括热压含有氮化硅的粉末混合物，致密化助剂如氧化钠，转化助剂如氧化镧和化合物如氧化镓 ，其增强了β-硅氮化物晶须的生长 - 在使得具有高纵横比的β-硅氮化物晶须的致密化和原位形成的条件下。 公开了一种具有高断裂韧性和高断裂强度的新型氮化硅陶瓷，其包括β-氮化硅结晶相，其中该相的至少约20体积百分数为晶须的形式，其平均纵横比为至少约2.5; 含有致密化助剂的玻璃质第二相，转化助剂，增强β-硅氮化物晶须生长的化合物和一定量的二氧化硅; 并且不大于作为其它相的总重量的约10重量％。 玻璃相还可以包括少量，例如，至多5.0重量％，基于陶瓷的总重量，氮化铝或氮化硼。 玻璃相任选地包括一定量的第二增强材料，例如碳化硅晶须。