Homework 05 Results

E-leaning Homework– Apirat – คําถามข้อ 5

จงเขียนผลการทดลอง (results) สําหรับบทความของท่าน

Results There are two glass composition groups which varied ratio of MgO:CaO by 1:2 and 2:1 in glass compositions. The first group start by CM1 and the second one start by CM2. 5 and 10 % mol of Na2O and K2O were added to study their effect on thermal expansion. The result of glass preparation show that all glass composition can be melted completely at 1450°C. As receive glass show clear color and no undisolve phase or crystalline phase. The Tg and Tc analysis of glass samples using DTA show in table 1. Some glasses have more than one exothermic peak of crystallization temperature such as CM13. DTA curve in Fig. 1 shows endothermic curve of its glass transition at Tg and exothermic peak of the first and the second crystallization temperature at Tc1 and Tc2 respectively.

Table 1 Differential thermal analysis results (Tg: glass transition temperature, Tc1: the first crystallization temperature, Tc2: the second crystallization temperature) DTA results

CM11

CM12

CM13

CM14

CM21

CM22

CM23

CM24

Tg (°C)

724

727

654

667

730

625

640

684

Tc1 (°C)

927

931

740

862

925

847

748

892

-

824

-

-

-

834

-

Tc2 (°C)

Tg

Tc1

Fig. 1 DTA curve of CM13 glass

Tc2

E-leaning Homework– Apirat –

Table 2 Dilatometric result of the bulk glass specimens and the specimens after sintering at 900oC/2h (Tg: glass transition temperature, Tc1: the first crystallization temperature, Tc2: the second crystallization temperature) Dilatometric results

CM11

CM12

CM13

CM14

CM21

CM22

CM23

CM24

Tg (°C)

730

714

653

642

640

595

636

647

Td (°C)

785

776

709

717

777

651

688

719

CTE x10-6 ºC -1

8.13

7.88

11.5

11.21

7.21

11.68

10.4

10.27

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

8.72

8.52

12.98

13.83

8.71

12.55

13.28

14.19

Bulk glass

Sintered specimens Tg (°C) Td (°C) -6

CTE x10 ºC

-1

Dilatometric results in table 2 show glass transition temperature and softening temperature acquired by dilatometric measurement. Fig.2 show the position of Tg and Td point on the thermal expansion curve of CM13 bulk glass. AISI 430 stainless steel has a thermal expansion 11.5 x10-6 ºC -1 (100 - 900 ºC), which its thermal expansion curve compare with CM13 glass and sintered specimen in Fig.3

1.0

Td

.8

dL/L0 (%)

Tg .6

.4

.2

0.0 0

100

200

300

400

500

600

700

800

O

Temperature ( C)

Fig. 2 Thermal expansion curve of CM13 glass show glass transition temperature (Tg) and softening temperature (Td)

E-leaning Homework– Apirat –

1.4 CM13 sintered CM13 glass AISI430 SS

1.2 1.0

dL/L0 (%)

.8 .6 .4 .2 0.0

0

200

400

600

800

1000

O

Temperature ( C)

Fig. 3 Comparison of thermal expansion curve of CM13 glass, Cm13 sintered specimen and AISI430 stainless steel The powder of glass ceramics which sintered at 900°C for 2 h was determined the phases analysis using Xray diffraction technique. The results show in table 3. Table 3 Primary crystalline phases in glass specimens after 900°C for 2 h analyzed by XRD technique Sample

CM11

CM12

CM13

CM14

CM21

CM22

CM23

CM24

Primary crystalline phases

Di+Cl

Di

Ak+Ne

Ge+Ka+Cl

Cl+Di

Ak+Ne

Ne+Di+Fo

Ka+Di

Di = Diopside (CaMgSi2O6)

Ak = Akermanite (Ca2Mg(Si2O7)) Ne = Nepheline (NaAlSiO4)

Cl = Clinoenstatite MgSiO3

Fo = (Forsterite Mg2SiO4)

Ge = (Gehlenite Ca2Al2SiO7)

Ka = Kaliophilite (KAlSiO4) The sandwich test results of AISI 430 stainless steel plates and glass ceramic pasted after joining at 900°C for 2 h show in table 4. Five tested specimens are good adjoining by using glass ceramic pastes.

E-leaning Homework– Apirat – Table 4 The sandwich test results of joining between AISI 430 stainless steel plates and glass ceramic Paste sample

Macroscopic observation

CM11

Detached

CM12

Detached

CM13

Adjoining

CM14

Adjoining

CM21

Detached

CM22

Adjoining

CM23

Adjoining

CM24

Adjoining