Hi Murugan,
Thanks for using Syncfusion products.
For changing the border width and color of a pie chart, the properties "Style.Border.Width" and "Style.Border.Color" of series can be used. Currently, it is not possible to change the border width and color only at the circumference of the pie chart. Because when using the above properties, width and color will also be set to each pie slices of the pie chart.
We have also attached a screenshot of a pie chart when the border width and color are changed.
Please let us know if you have any concerns.
Regards,
Anandaraj
Pie chart border width_c1253a67.zip