Powder Injection Moulding of Alumina Using PEG/PVB Binder Systems

2013 ◽  
Vol 545 ◽  
pp. 173-176 ◽  
Author(s):  
Nutthita Chuankrerkkul ◽  
Pat Sooksaen ◽  
Piyawan Pakunthod ◽  
Tutiyachan Kosalwit ◽  
Wanwara Pinthong
Keyword(s):  
Injection Moulding ◽  
Removal Rate ◽  
Minor Component ◽  
Polyvinyl Butyral ◽  
Major Constituent ◽  
Powder Injection ◽  
Alumina Powder ◽  
Water Leaching ◽  
Powder Injection Moulding ◽  
Feedstock Preparation

Powder injection moulding (PIM) is a process that is suitable for a fabrication of small and complex shape components. It consists of 4 main steps: feedstock preparation by mixing powder and binder, injection moulding of the prepared feedstock into the desired mould, removal of the binder and finally sintering to obtain materials with specific properties. In this study, powder injection moulding of alumina (Al2O3), using polyethylene glycol (PEG) based binder systems, was investigated. PEG is soluble in water; therefore, the use of organic solvents required for debinding of wax-based binder system can be avoided. PEG with a molecular weight of either 1500 or 4000 was used as a major constituent together with polyvinyl butyral (PVB) as a minor component. Stearic acid was also added during feedstock preparation to act as a lubricant. After mixing the powder with the binder, a variety of Al2O3 feedstocks were injected into the moulds. The mouldings were prepared by a laboratory-scaled plunger-typed machine. Debinding was carried out using a combination of solvent extraction and thermal debinding. Water leaching tests were performed at 30 and 50 °C to study PEGs removal rate. The pyrolysis of PVB was completed during ramping up of the mouldings to the sintering temperature. The mouldings were subjected to sintering at 1500 °C in air. It was found from the study that PEG/PVB binder systems can be used for the preparation of alumina powder injection moulding feedstocks. Specimens retained their shapes during and after leaching of the PEGs.

Effects of Water Temperatures on Water-Soluble Binder Removal in Ceramic Materials Fabricated by Powder Injection Moulding

2015 ◽  
Vol 659 ◽  
pp. 90-95
Author(s):  
Wantanee Buggakupta ◽  
Nutthita Chuankrerkkul ◽  
Juthathep Surawattana
Keyword(s):  
Injection Moulding ◽  
Removal Rate ◽  
Ceramic Powder ◽  
Polyvinyl Butyral ◽  
Ceramic Materials ◽  
Water Soluble ◽  
Powder Injection ◽  
Powder Materials ◽  
Binder Removal ◽  
Powder Injection Moulding

This work focuses on the debinding conditions of the ceramic materials fabricated by powder injection moulding. Ceramic powder materials, including alumina and alumina-based composites were prepared as feedstocks and mixed with water-soluble polyethylene glycol (PEG) and polyvinyl butyral (PVB). The PEG/PVB binder mixture, with PEG to PVB ratio of 85:15 by weight and powder loading of 44 vol%, were thoroughly mixed and injected into the mould at the temperature of 190 °C to obtain rod-like specimens. Prior to sintering, the as-injected specimen was then leached in water, the temperature of which was varying from 30 (ambient temperature), 45 to 60 °C, in order to get rid of PEG and leave the specimens in shape by PVB. The rate of PEG removal according to different water temperatures was investigated. The experimental results suggested that PEG could completely be eliminated by 45 and 60 °C water without any dimensional disintegration in 5 hours whereas those leached in 30 °C water showed only 70% PEG removal. Higher water temperatures led to fast PEG removal rate at the beginning and then gradually decreased with elapsed times.

Properties of Porous Alumina Fabricated by Ceramic Injection Moulding Using Environmentally Friendly Binder

2012 ◽  
Vol 506 ◽  
pp. 238-241 ◽  
Author(s):  
J. Surawatthana ◽  
Nutthita Chuankrerkkul ◽  
Wantanee Buggakupta
Keyword(s):  
Injection Moulding ◽  
Porous Alumina ◽  
Polyvinyl Butyral ◽  
Powder Injection ◽  
Water Leaching ◽  
Moulding Process ◽  
Powder Injection Moulding ◽  
Injection Moulding Process ◽  
Thermal Debinding ◽  
Ceramic Injection Moulding

Porous alumina (Al2O3) ceramics were fabricated by powder injection moulding process. The feedstocks, composed of 44 50 vol% of Al2O3 powder, could be prepared using a composite binder, consisting of polyethylene glycol (PEG) and polyvinyl butyral (PVB). Debindings were carried out using a combination of water leaching of the PEG and thermal debinding of the PVB. It was observed that the removal of the PEG was fast at the initial stage and more than 90 wt% of the PEG could be removed within 4 hours. Sintering was performed in argon atmosphere at 1600 °C. The sintered specimens had apparent porosity in range of 26-32 %, depending on the feedstock compositions. The flexural strength values were in range of 90-140 MPa while the hardness values were in range of 5-9 GPa. It was found that both the strength and hardness of the specimens were increased with increasing powder loading.

Influence of Specimen Dimensions and Temperature on the Debinding Behavior of Alumina Feedstock

2014 ◽  
Vol 608 ◽  
pp. 170-174 ◽  
Author(s):  
Nawamin Chomsirigul ◽  
Onwadee Khuanthong ◽  
Pat Sooksaen ◽  
Nutthita Chuankrerkkul
Keyword(s):  
Surface Area ◽  
Removal Rate ◽  
Volume Ratio ◽  
Minor Component ◽  
Polyvinyl Butyral ◽  
Powder Injection ◽  
Cylindrical Shape ◽  
Water Leaching ◽  
Injection Process ◽  
Debinding Process

This work investigated the influence of specimen dimensions and temperature on the debinding behavior of alumina feedstock for powder injection process. Polyethylene glycol (PEG) was used as a based binder. It is soluble in water therefore the use of wax-based binder system can be avoided. PEGs with a molecular weight of 1500 and 4000 were mixed with polyvinyl butyral (PVB) a minor component. Stearic acid was added during feedstock preparation to act as a lubricant. Debinding process was carried out using a water leaching test at 30 and 70 °C to study for PEG removal rate. Specimens retained their shapes after leaching of the binders. In general, the rate of binder removal increased at initial stage then slowed down at longer leaching times. A faster debinding rate was achieved at 70 °C when compared to 30 °C. In addition, samples with a higher surface area to volume ratio (As/V) led to an increase in the %PEG removal rate. This study also showed the relationship between %PEG removal as a function of different surface area to volume ratio (As/V) which can be helpful in predicting %PEG removal for any other samples having cylindrical shape.

Microstructure and Properties of Zirconia Toughened Alumina Fabricated by Powder Injection Moulding

2015 ◽  
Vol 659 ◽  
pp. 116-120
Author(s):  
Nutthita Chuankrerkkul ◽  
Rattanaporn Charoenkijmongkol ◽  
Punnapa Somboonthanasarn ◽  
Chiraporn Auechalitanukul ◽  
Ryan C. McCuiston
Keyword(s):  
Injection Moulding ◽  
Polyvinyl Butyral ◽  
Water Soluble ◽  
Powder Injection ◽  
Water Leaching ◽  
Moulding Process ◽  
Powder Injection Moulding ◽  
Injection Moulding Process ◽  
Moulding Machine ◽  
Zirconia Toughened Alumina

Zirconia toughened alumina (ZTA) ceramic has been fabricated by the powder injection moulding process. The ZTA ceramic, composed of 80 wt% alumina and 20 wt% zirconia, was mixed with a water-soluble, multi-component binder system. The binder ingredients were polyethylene glycol (PEG), polyvinyl butyral (PVB) and stearic acid (SA). Powder injection moulding was performed with powder loadings in the range of 48-52 vol%, using a laboratory-scale injection moulding machine. Water leaching was used for partial binder removal prior to thermal debinding and then sintering at 1650 °C for 2 hours. Microstructural examination of the ZTA ceramic revealed that zirconia inhibited alumina grain growth and, therefore, improved the mechanical and physical properties of the specimens. It was found that powder loading had an influence on density, hardness and strength of the specimens. A flexural strength of 334 MPa and hardness value of 2093 kg/mm2 was obtained from specimens injection moulded with 52 vol% powder loading feedstock. The highest sintered density achieved was 97% of the theoretical value.

Role of Tungsten Carbide Reinforcement on Alumina Matrix Composites Fabricated by Powder Injection Moulding

2014 ◽  
Vol 608 ◽  
pp. 230-234 ◽  
Author(s):  
Nutthita Chuankrerkkul ◽  
Wantanee Buggakupta ◽  
Juthathep Surawatthana
Keyword(s):  
Tungsten Carbide ◽  
Injection Moulding ◽  
Polyvinyl Butyral ◽  
Powder Injection ◽  
Matrix Composites ◽  
Alumina Matrix ◽  
Powder Injection Moulding ◽  
Alumina Composites ◽  
Particulate Reinforced

In this work, properties of tungsten carbide (WC) particulate reinforced alumina matrix composites fabricated by powder injection moulding (PIM) technology were reported. The 90 wt% of Al2O3 and 10 wt% of WC powders were mixed with a composite binder, composed of 85 wt% polyethylene glycol (PEG) and 15 wt% polyvinyl butyral (PVB). Feedstocks of alumina and alumina-tungsten carbide composites having powder loading from 44 to 52 vol% were prepared and injected into a mould of rectangular shape. The binders in the mouldings were leached by water and then thermally debinded prior to sintering at 1600 °C for 2 hours in argon atmosphere. Strength, Density, hardness and density of the alumina and alumina composites’ bodies were compared and reported. It was found that the properties of sintered specimens, both Al2O3 and Al2O3/WC composites, increased with increasing powder loadings. The properties enhancement was also presented in the WC reinforced alumina composites. The composite of 52 vol% powder loading had flexural strength and hardness of 253.8 MPa and 12.5 GPa, respectively.

Application of PEG/PMMA Binder for Powder Injection Moulding of Hardmetals

2007 ◽  
Vol 561-565 ◽  
pp. 953-956 ◽  
Author(s):  
Nutthita Chuankrerkkul ◽  
Hywel A. Davies ◽  
Peter F. Messer
Keyword(s):  
Injection Moulding ◽  
High Performance ◽  
Cost Effective ◽  
Processing Parameters ◽  
Powder Injection ◽  
Water Leaching ◽  
Powder Metallurgical Process ◽  
Powder Injection Moulding ◽  
Small Complex ◽  
A Minor

Powder injection moulding (PIM) is a cost effective powder metallurgical process for the fabrication of small, complex-shaped components for high performance applications. A binder system, which comprises a major fraction of polyethylene glycol (PEG) and a minor fraction of a very finely dispersed polymethyl methacrylate (PMMA), has been applied for tungsten carbide (WC) – cobalt (Co) hardmetal powders. PEG can be removed rapidly by water leaching and PMMA is removed by subsequent pyrolysis when the components are ramped up to the sintering temperature. In this work, the development of feedstock formulations and of the processing parameters for a successful injection moulding and to achieve high density has been investigated. The present study has demonstrated that the binder can be employed for the production of WC-Co hardmetal components by PIM process. The maximum density achieved thus far is 97% of the theoretical value.

scholarly journals Recent advances in PIM technology I

2008 ◽  
Vol 40 (1) ◽  
pp. 79-88 ◽  
Author(s):  
B.S. Zlatkov ◽  
E. Griesmayer ◽  
H. Loibl ◽  
O.S. Aleksic ◽  
H. Danninger ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Flow Diagram ◽  
Powder Injection ◽  
Main Process ◽  
Metal Parts ◽  
Surface Active Agents ◽  
Powder Injection Moulding ◽  
Powder Characteristics ◽  
Feedstock Preparation ◽  
Stainless Steel 316

In this article the state of art of the PIM (Powder Injection Moulding) technology is given in brief. The main process flow diagram consisting of four steps: feedstock preparation, injection moulding (green samples forming), the debinding (binder removing) procedure and the sintering process was described. After that the materials for binders and additives for the surface active agents were mentioned in brief. The metal injection moulding (MIM) process was analysed in more detail: MIM- stainless steels, MIM-copper and MIM-aluminium as the most metals common in MIM metal parts production. After that our results of MIM stainless steel 316 L and MIM copper are given. The main powder characteristics, the shrinkage and density of the sintered samples were compared for isostatically pressed PM (powder metallurgy) samples and MIM formed samples. The SEM fractographs of MIM and PM samples are given for MIM green parts, debinded (brown) parts and sintered parts, and PM green parts and sintered parts. The results obtained were compared with literature data before they were applied in metal parts production.

scholarly journals Recent advances in PIM technology I

2008 ◽  
Vol 40 (1) ◽  
pp. 79-88
Author(s):  
B.S. Zlatkov ◽  
E. Griesmayer ◽  
H. Loibl ◽  
O.S. Aleksic ◽  
H. Danninger ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Flow Diagram ◽  
Powder Injection ◽  
Main Process ◽  
Metal Parts ◽  
Surface Active Agents ◽  
Powder Injection Moulding ◽  
Powder Characteristics ◽  
Feedstock Preparation ◽  
Stainless Steel 316

In this article the state of art of the PIM (Powder Injection Moulding) technology is given in brief. The main process flow diagram consisting of four steps: feedstock preparation, injection moulding (green samples forming), the debinding (binder removing) procedure and the sintering process was described. After that the materials for binders and additives for the surface active agents were mentioned in brief. The metal injection moulding (MIM) process was analysed in more detail: MIM- stainless steels, MIM-copper and MIM-aluminium as the most metals common in MIM metal parts production. After that our results of MIM stainless steel 316 L and MIM copper are given. The main powder characteristics, the shrinkage and density of the sintered samples were compared for isostatically pressed PM (powder metallurgy) samples and MIM formed samples. The SEM fractographs of MIM and PM samples are given for MIM green parts, debinded (brown) parts and sintered parts, and PM green parts and sintered parts. The results obtained were compared with literature data before they were applied in metal parts production.

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