Fig.2. ItwasobviousthatCeO2 wasalso

Fig.2. ItwasobviousthatCeO2 wasalsoaneffective
additiontoimprovethepropertiesofWC–40vol%Al2O3
composites.WhentheCeO2 contentwassmallerthan
0.1wt%,therelativedensityincreasedandthegrainsize
ofWCdecreased.Dopingof0.1wt%CeO2 in WC–40
vol%Al2O3 compositesincreasedtherelativedensityfrom
98.38%upto98.82%,however,furtheradditionofCeO2
resultedinsharpdecreaseofrelativedensity,asshownin
Fig.2a. ForundopedWC–40vol%Al2O3 composites,
thegrainsizeofWCwas3.92 mm, theadditionof
0.1wt%CeO2 significantlydecreasedthegrainsizeofWC
to 2.71 mm. However,itwasfoundthattheWCgrain
sizeincreasedwiththeincreasingCeO2 contentinthe
WC–40vol%Al2O3–CeO2 system,whentheCeO2 content
increasedto1wt%,theWCgrainsizereached4.03 mm, 1.5
timeslargerthanthatofthe0.1wt%CeO2 doped
WC–40vol%Al2O3 composites.From Fig.2b, itcanbe
seenthattheVickershardnessandfracturetoughnessof
WC–40vol%Al2O3–CeO2 compositesweresignificantly
increasedwiththeadditionof0.05wt%CeO2 and
0.1wt%CeO2, furtheradditionofCeO2 resultedinlowered
Vickershardnessandfracturetoughnessvalues.Itwasclear
thatwhentheCeO2 contentexceeded0.1wt%,theVickers
hardnessofWC–40vol%Al2O3–CeO2 compositeswere
lowerthanthatoftheundopedone.Itmeansthatacritical
contentofCeO2 couldrestraintheWCgraingrowthand
improvethedensityofWC–40vol%Al2O3 composites
effectively,abovewhichgraingrowthwouldoccur,and
therelativedensitywoulddecreased,resultinginthe
reducedVickershardnessandfracturetoughness.
The ionsofadditivessegregationtograinandphase
boundarieswasquitegeneralphenomenonwidely
observed inceramics [20,21], andwasparticularlyimpor-
tant todiffusionprocessduringsinteringofceramics.The
MgO andCeO2 additivesdispersedintheWC–
40 vol%Al2O3 compositesmayalsopredominantlyoccu-
pied theintergranularpositionsduetothemismatchofthe
ionic radiiandstrainenergyofCeO2, Al2O3, andWC.
Although thegrainboundariesinpureAl2O3 were
reportedtocarryapositivecharge [22], thesegregation
of CeonAl2O3 boundarieswasnotexplicablebythespace
charge modelsincetetravalentandisoelectrictrivalent

Results (Thai) 1:

Fig.2. wasalsoaneffective ItwasobviousthatCeO2
additiontoimprovethepropertiesofWC–40vol % Al2O3
คอมโพสิตContentwassmallerthan
0.1wt%,therelativedensityincreasedandthegrainsize
ofWCdecreased.Dopingof0.1wt%CeO2 WhentheCeO2 ใน WC–40
compositesincreasedtherelativedensityfrom
98.38%upto98.82%,however,furtheradditionofCeO2
resultedinsharpdecreaseofrelativedensity,asshownin
Fig.2a % Al2O3 vol ForundopedWC–40vol % Al2O3 คอมโพสิต,
thegrainsizeofWCwas3.92 mm, theadditionof
0.1wt%CeO2 significantlydecreasedthegrainsizeofWC
2.71 มม. อย่างไรก็ตาม itwasfoundthattheWCgrain
sizeincreasedwiththeincreasingCeO2 contentinthe
WC–40vol % Al2O3–CeO2 ระบบ whentheCeO2 content
increasedto1wt%,theWCgrainsizereached4.03 mm, 1.5
timeslargerthanthatofthe0.1wt%CeO2 doped
WC–40vol % Al2O3 คอมโพสิตจาก Fig.2b, itcanbe
seenthattheVickershardnessandfracturetoughnessof
WC–40vol % Al2O3–CeO2 compositesweresignificantly
increasedwiththeadditionof0.05wt%CeO2 and
0.1wt%CeO2, furtheradditionofCeO2 resultedinlowered
Vickershardnessandfracturetoughnessvalues.Itwasclear
thatwhentheCeO2 contentexceeded0.1wt%,theVickers
hardnessofWC–40vol%Al2O3–CeO2 compositeswere
lowerthanthatoftheundopedoneItmeansthatacritical
contentofCeO2 couldrestraintheWCgraingrowthand
improvethedensityofWC–40vol % Al2O3 คอมโพสิต
ได้อย่างมีประสิทธิภาพ abovewhichgraingrowthwouldoccur และ
therelativedensitywoulddecreased, resultinginthe
reducedVickershardnessandfracturetoughness.
ionsofadditivessegregationtograinandphase
boundarieswasquitegeneralphenomenonwidely
สังเกต [20,21], inceramics andwasparticularlyimpor-
tant todiffusionprocessduringsinteringofceramicsใน
MgO andCeO2 additivesdispersedintheWC–
40 vol % Al2O3 compositesmayalsopredominantlyoccu-
theintergranularpositionsduetothemismatchofthe นก
ionic radiiandstrainenergyofCeO2, Al2O3, andWC.
แม้ถูก thegrainboundariesinpureAl2O3
reportedtocarryapositivecharge [22], thesegregation
ของ CeonAl2O3 boundarieswasnotexplicablebythespace
ค่าธรรมเนียม modelsincetetravalentandisoelectrictrivalent

Results (Thai) 2:

รูปที่ 2 ItwasobviousthatCeO2 wasalsoaneffective
additiontoimprovethepropertiesofWC-40vol% Al2O3
composites.WhentheCeO2 ใน WC-40 ฉบับ% Al2O3 ForundopedWC-40vol% ผสม Al2O3, thegrainsizeofWCwas3.92 มม. theadditionof 0.1wt% CeO2 significantlydecreasedthegrainsizeofWC ถึง 2.71 มิลลิเมตร แต่ itwasfoundthattheWCgrain sizeincreasedwiththeincreasingCeO2 contentinthe WC-40vol% ระบบ Al2O3-CeO2, whentheCeO2 เนื้อหาincreasedto1wt% theWCgrainsizereached4.03 มม. 1.5 % timeslargerthanthatofthe0.1wt CeO2 ยาWC-40vol% Al2O3 composites.From Fig.2b, itcanbe seenthattheVickershardnessandfracturetoughnessof WC-40vol Al2O3% -CeO2 compositesweresignificantly increasedwiththeadditionof0.05wt% CeO2 และ0.1wt% CeO2, furtheradditionofCeO2 resultedinlowered Vickershardnessandfracturetoughnessvalues.Itwasclear thatwhentheCeO2 contentexceeded0.1wt% theVickers hardnessofWC-40vol% Al2O3-CeO2 compositeswere lowerthanthatoftheundopedone.Itmeansthatacritical contentofCeO2 couldrestraintheWCgraingrowthand improvethedensityofWC-40vol Al2O3% ionsofadditivessegregationtograinandphase boundarieswasquitegeneralphenomenonwidely inceramics สังเกต [20,21] andwasparticularlyimpor- คัญ todiffusionprocessduringsinteringofceramics.The MgO andCeO2 additivesdispersedintheWC- 40 ฉบับ% Al2O3 compositesmayalsopredominantlyoccu- Pied theintergranularpositionsduetothemismatchofthe radiiandstrainenergyofCeO2 อิออน, Al2O3, andWC แม้ว่า thegrainboundariesinpureAl2O3 มีreportedtocarryapositivecharge [22], thesegregation ของ CeonAl2O3 boundarieswasnotexplicablebythespace ค่าใช้จ่าย modelsincetetravalentandisoelectrictrivalent

Results (Thai) 3:

fig.2 . itwasobviousthatceo2 wasalsoaneffective
additiontoimprovethepropertiesofwc – 40vol % Al2O3

composites.whentheceo2 contentwassmallerthan 0.1wt % , therelativedensityincreasedandthegrainsize
ofwcdecreased . dopingof0.1wt CeO2 ในสุขา– 40 %
%
% Vol Al2O3 compositesincreasedtherelativedensityfrom 98.38 upto98.82 เปอร์เซ็นต์ อย่างไรก็ตาม furtheradditionofceo2 resultedinsharpdecreaseofrelativedensity asshownin
,
fig.2a .forundopedwc – 40vol % อะลูมิเนียมคอมโพสิต theadditionof

thegrainsizeofwcwas3.92 มม. 0.1wt % CeO2 significantlydecreasedthegrainsizeofwc
ถึง 2 มิลลิเมตร อย่างไรก็ตาม itwasfoundthatthewcgrain

sizeincreasedwiththeincreasingceo2 contentinthe สุขา– 40vol % Al2O3 – CeO2 ระบบ whentheceo2 เนื้อหา
increasedto1wt % , thewcgrainsizereached4.03 มม. 1.5
%
timeslargerthanthatofthe0.1wt CeO2 ที่มีห้องสุขาและ 40vol % อะลูมิเนียมคอมโพสิตจาก fig.2b itcanbe

, seenthatthevickershardnessandfracturetoughnessof สุขา– 40vol % Al2O3 – CeO2 compositesweresignificantly increasedwiththeadditionof0.05wt CeO2 และ

%
% 0.1wt CeO2 furtheradditionofceo2 resultedinlowered , vickershardnessandfracturetoughnessvalues . itwasclear
thatwhentheceo2 contentexceeded0.1wt % , thevickers
hardnessofwc – 40vol % Al2O3 – CeO2 compositeswere
lowerthanthatoftheundopedone .itmeansthatacritical

contentofceo2 couldrestrainthewcgraingrowthand improvethedensityofwc – 40vol % อะลูมิเนียมคอมโพสิต
ได้อย่างมีประสิทธิภาพ abovewhichgraingrowthwouldoccur และ therelativedensitywoulddecreased reducedvickershardnessandfracturetoughness resultinginthe

, .


ionsofadditivessegregationtograinandphase boundarieswasquitegeneralphenomenonwidely สังเกต inceramics [ 20,21 andwasparticularlyimpor -
]จึง todiffusionprocessduringsinteringofceramics .

additivesdispersedinthewc MgO andceo2 – 40 เล่มที่ % Al2O3 compositesmayalsopredominantlyoccu -

radiiandstrainenergyofceo2 Al2O3 ลายพร้อย theintergranularpositionsduetothemismatchofthe อิออน , , andwc .
ถึงแม้ว่า thegrainboundariesinpureal2o3 ถูก
reportedtocarryapositivecharge [ 22 ] thesegregation ceonal2o3 boundarieswasnotexplicablebythespace

ของค่าใช้จ่าย modelsincetetravalentandisoelectrictrivalent