Kochel am See, September 2014

Pressure slip casting for application in Technical Ceramics and the Refractory

Industry

It is now more than 6 years ago that the Institute of Ceramic, Glass and Construction Materials (IKGB)

of the TU Bergakademie Freiberg (TU-BAF = Technical University Mining College) and Dorst

Technologies, Kochel am See, have started their cooperation in the field of pressure slip casting. The

partners found themselves with good reason in 2008.

The team headed by Prof. Dr. C.G. Aneziris enjoys worldwide reputation for proven competence in

materials development and the packaging of ceramic materials.

Dorst Technologies can rely on decades of experience focusing on the development and manufacture

of pressing casting plants and moulds for the tableware and the sanitary ware industry.

It always suggested itself to use this technology, which is well-known from traditional ceramics, also

for engineering materials. In particular, applications from refractory ceramics are in the focusing,

since they call for large and increasingly precise components made of ceramic material. No power

plant, no incinerator and no steel mill can be run without efficient refractory ceramics.

Provided that suitable materials are available, the requirements on functional, temperature-resistant

and erosion-resistant components can be excellently met by pressure slip casting. This production

method also opens up new dimensions with regard to size, diversity of shape, and tolerances.

The developments at the IKGB exactly provide the ceramic slips which are required for pressure

casting.

The necessary machines and automation components differ only slightly from the known standard

plants. Therefore, development results can be very good transferred to industrial scale. However, the

key issues for successful implementation are the specific filling technology, mould manufacture and

individual process control

Within the framework of the partnership, Dorst has provided the TU-BAF with a modified pressure

casting plant DGM80 as a permanent loan for these developments. The necessary pressure casting

moulds will be supplied as required by the specific order.

We take this opportunity to express our thanks to Dipl.-Ing. Nora Gerlach from the TU-BAF for the

article, which you will find on the next pages, giving an excellent impression of the current research

at the institute and the results. The various interesting prospects for innovative applications of

pressure slip casting in technical ceramics and the refractory industry are made quite clear

Dipl.-Ing. Hans-Christian Schmidt

Technische Keramik und Magnetwerkstoffe,

New Business Development

TU Bergakademie Freiberg I Institut für Keramik, Glas- und Baustofftechnik I Agricolastraße 17 I 09599 Freiberg E-Mail: aneziris@ikgb.tu-freiberg.de I Tel.: ++49 (0) 3731 / 39-2608 I Fax: ++49 (0) 3731 / 39-2419

Internet: www.ikgb.de

Nora Gerlach, Institut für Keramik, Glas- und Baustofftechnik, TU-BAF, Freiberg/Sachsen, 2014

Pressure slip pressure casting at the Institute of Ceramic, Glass and Construction Materials

of the Technical University in Freiberg

Slip pressure casting of coarse and fine ceramic materials plays an important role at the Institute of

Ceramic, Glass and Construction Materials of the Technical University Bergakademie (TU-BAF).

Thanks to the generosity of the company DORST Technologies, the Institute can use a pressure

casting machine type DGM 80D. By means of a newly developed binding agent [1] it is possible, to

cast bodies free from china clay with a grain size up to 3 mm and to demould them dimensionally

stable. Depending on material and water content, casting times of 30 to 10 minutes can be realized.

The following materials have already undergone pressure slip casting: corundum (see fig. 1), mullite,

zirconium mullite, spinel, bonit, silicon carbide (SiC), zirconium dioxide (ZrO2) and carbon-bonded

aluminum oxide Al2O3 (see fig. 2) [2, 3].

Within the scope of special research (SFB799), also composites from steel and ceramics have been

cast with success.

Fig. 1: Plate made of corundum (220 x 220 x 40 mm³) Fig. 2: Plate made of carbon-bonded Al2O3

(220 x 220 x 40 mm³)

The analysis of the rheological behavior of the coarse-grained slip is carried out at the Institute using

a drop-ball viscometer. In addition, preliminary tests in a pressure nutsch filter can provide

information about the possible dehydration behavior during the later pressure slip casting process in

the system.

By means of computer tomography at the Institute, the samples manufactured by pressure casting

can undergo nondestructive analysis. Figure 3 illustrates the uniform coarse grain distribution in the

body after pressure slip casting.

TU Bergakademie Freiberg I Institut für Keramik, Glas- und Baustofftechnik I Agricolastraße 17 I 09599 Freiberg E-Mail: aneziris@ikgb.tu-freiberg.de I Tel.: ++49 (0) 3731 / 39-2608 I Fax: ++49 (0) 3731 / 39-2419

Internet: www.ikgb.de

Fig. 3: Coarse grain distribution (max. 3 mm) in the body, CT-scan, voxel size: 214,90 µm

[1] DE102012017822B3 Gerlach, N.; Aneziris, C.G.; Wenzel, C.: Verwendung eines Gemisches aus

Konjakmehl und Welan Gum als Binder für die keramische und pulvermetallurgische Formgebung,

19.09.2013

[2] Klippel, U.; Aneziris, C.G.; Metzger, A.J. (2011): Shaped coarse grained refractories by pressure slip

casting. Adv. Eng. Mater. 13 (1-2), pp. 68-76

[3] Schafföner, S.; Aneziris, C.G. (2012): Pressure slip casting of coarse grain oxide ceramics. Ceram.

Int. 38, pp. 417-422