Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>Boehmite</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times> (</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>γ</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>-AlOOH)</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>precipitate was obtained with aluminum nitrate as raw material and with ammonia as precipitator.</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>α</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>-Al</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>2</SUB>O</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>3</SUB></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times> micro powders were directly prepared under hydrothermal condition with the obtained boehmite as precursor and with nano-sized </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>α</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>-Al<SUB>2</SUB></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>O</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>3</SUB></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB> </SUB>as seed crystal. With increasing reaction temperatures from <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="380" UnitName="℃">380 <SPAN lang=EN-US style="FONT-FAMILY: 宋体; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-hansi-font-family:><SPAN lang=EN-US>℃</SPAN></SPAN></st1:chmetcnv> to <st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="460" UnitName="℃">460 <SPAN lang=EN-US style="FONT-FAMILY: 宋体; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-hansi-font-family:><SPAN lang=EN-US>℃</SPAN></SPAN></st1:chmetcnv> for a holding time of 8 h,crystals were found to grow from 2.1 </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>μ</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>m to 3.5 </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>μ</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>m in size.The particle size increased from </SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>2.3 </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>μ</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>m </SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>to 4.6 </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>μ</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>m by varying the holding time from 8 h to 36 h at <st1:chmetcnv w:st="on" TCSC="0" NumberType="1" Negative="False" HasSpace="True" SourceValue="400" UnitName="℃">400 <SPAN lang=EN-US style="FONT-FAMILY: 宋体; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-hansi-font-family:><SPAN lang=EN-US>℃</SPAN></SPAN></st1:chmetcnv>.The grain-growth kinetics of </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>α</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>-Al<SUB>2</SUB></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>O</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>3</SUB></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>&nbsp;</SUB></SPAN></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times> crystal under hydrothermal condition was found to follow the equation,</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>D<SUP>n</SUP>=&nbsp;D<SUP>n</SUP><SUB>0</SUB>+k<SUB>0</SUB>&#8226;t&#8226;e<SUP>(-Ea/RT) </SUP></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>with a grain-growth exponent </SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>n=2</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times> and an activation energy of </SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>E</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>a</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>=47.37 kJ/mol.The mechanism of </SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: " Roman?; New Times Roman?? ?Times mso-bidi-font-family: mso-hansi-font-family:>α</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times>-Al</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>2</SUB>O</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times><SUB>3</SUB></SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: " AR-SA? mso-bidi-language: ZH-CN; mso-fareast-language: EN-US; mso-ansi-language: 1.0pt; mso-font-kerning: 宋体; mso-fareast-font-family: 12.0pt; mso-bidi-font-size: Roman?; New Times> crystal growth was investigated.</SPAN>