Use of rare-earth metal oxides for decoration of porcelain

Abstract

A variant of use of rare-earth metal oxides for decoration of porcelain is examined. The effect of these oxides on phase formation and on the character of coloring of the structure on incorporation in the paste is examined.Underglaze painting is widely used as a type of decoration in many porcelain factories in the country. The palette of different underglaze colors is greatly limited by the fact that the coloring pigments can burn off or be reduced at high temperatures (1300 -1420°C) and in the reducing character of the gas medium [1,2]. For this reason, it becomes necessary to use high-temperature coloring compounds which are stable in these conditions. Rare-earth metal oxides (REMO) are such compounds. They can be used as components of paints for decorating porcelain articles and as a constituent part of the mass which has the property of coloring porcelain. Some properties and the color range of a series of REMO are reported in Table 1 [3].Coloring porcelain paste allows manufacturing porcelain for different applications: artistic, household, industrial, etc. One of the main problems in coloring the paste is giving the porcelain previously known coloristic and esthetic characteristics while preserving all of the properties of classic porcelain.The optimum amount of REMO (5.0 -7.5%) [4] was added to porcelain paste of the following composition (mass content, %): 66.21 SiO 2 , 21.12 Al 2 O 3 , 0.29 Fe 2 O 3 , 0.69 CaO, 0.47 MgO, 1.83 K 2 O, 0.85 Na 2 O, 0.13 TiO 2 , 6.31 calcination loss.The porcelain samples underwent microscopic analysis [5,6]. Petrographic analysis showed (Table 2) that incorporation of REMO in the porcelain changed its structure. With respect to the character of the effect of the REMO on coloration of the porcelain samples, they can be divided into two groups:forming crystal aggregates in the structure of the porcelain (Er 2 O 3 , CeO 2 ); not forming a crystalline phase but forming colored glass (Nd 2 O 3 , Pr 6 O 11 ).The boundaries of the pseudomorphoses with respect to feldspar are basically preserved and the size of the mullite needle network is 2 -10 mm, less frequently up to 15 -20 mm, the mullite in the basic paste is less than 1 mm in size, and aggregates are pronounced.All of the REMO alter the porosity and increase the amount of glass phase, manifested by perfection of the shape of the pores and slight improvement in the character of mullitization. Their effect is especially marked in blue porcelain containing Nd 2 O 3 (with respect to the structure, this is a porcelain of a normal degree of ripeness but with slightly larger pores).A possible cause of the appearance of isolated pores and sections of glass in incorporation of REMO is inadequate dispersion of the pigment in the paste, which can be eliminated by combined disaggregation of the components of the porcelain paste.X-ray phase analysis of the porcelain samples with REMO showed that CeO 2 forms an eutectic with mullite while Nd 2 O 3 and Er 2 O 3 forms the chemical compounds 2Nd 2 O 3 × 3SiO 2 and Er 2 O 3 × 2SiO 2 . An in...

Effect of Praseodymium Oxide on Thermal and Optical Properties in Raw Transparent glaze

“…Thus, the materials containing rare‐earth metal oxides (i.e., Nd 2 O 3 , Sm 2 O 3 , Er 2 O 3 , CeO 2 , and Pr 6 O 11 ) can manifest a certain color as a potential colorant in the environmentally benign pigments, that is, CeO 2 ‐Pr 6 O 11 ‐La 2 O 3 , CeO 2 ‐Pr 6 O 11 ‐Gd 2 O 3 , CeO 2 ‐Pr 6 O 11 ‐Sm 2 O 3 , CeO 2 ‐Pr 6 O 11 ‐Nd 2 O 3 , and CeO 2 ‐Pr 6 O 11 . Therefore, these rare‐earth metal cations were used in the production of colored porcelain, which generally have a low toxicity rating . Kondrukevich et al .…”

“…reported that Nd 2 O 3 was a weak pigment in hard porcelain, and the optimal content of Nd 2 O 3 in porcelain is 5–7 wt.%. Vlasov et al . also found that rare‐earth metal oxides such as CeO 2 , Pr 6 O 11 , Nd 2 O 3 , and Er 2 O 3 can be used for decorating porcelain.…”

Synthesis of neodymium-containing pigments

“…Investigators have recently turned their attention to the use of rare-earth elements for decorating porcelain and synthesis of ceramic pigments [1].…”