New data of phosphatized globular fossils from Weng'an biota in the Ediacaran Doushantuo Formation and the problem concerning their affinity

In recent years much attention has been paid to phosphatized spheroidal fossils found in the Sinian Doushantuoan phosphorites in Weng an, Guizhou Province.

The phosphatized spheroidal fossils are a kind of microfossils, which are morphologically characterized by having a spherical appearance, either with spinal and tuberculate sculptures or with smooth outer surfaces, and were preservationally phosphatized during early diagenesis.

It is justified by the observed results that non-metallic inclusion can act as the heterogeneous nuclei of nodular graphite in this paper.

Adding different alloy combination of RE, copper and titanium, then through gestation and nodulizing disposal, we got the fine texture of ferrite pearlite and spheroidal graphite.

Spheroidal graphite can be observed in the region approaching surface of the smaller section size gray iron bars by continuous cast The experiment shows that spharical graphite may crystallize in commercial gray cast iron with suitable chemical composition under certain cooling rate This phenomenon can be explained by the mechanism of diffusion controlled growth of graphit

The fracture behaviour of cast irons with graphite irregularity S=0 and spheroidal graphite iron under three different stress modes was investigated.

The best nucleus of spherical graphite should be some non-metallic impurities or some bubbles formed by surface active elements,which have low boiling points.

Most nuclei with spherical or near spherical shape can grow up into spherical graphite, while nuclei with no regular shape can hardly grow.

Natural spectroscopically pure scalelike graphite powder(400 mesh) and spherical graphite(400 mesh) were used respectively as carbon source,Fe-based alloy powder(75 μm) was used as solvent-catalyst.